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PreAP Physics
Spring 2012
Extra Review Problems
Unit 7: Impulse and Momentum
1. In order to catch a ball, a baseball player moves his or her hand backward in the direction of the ball's
motion. Doing this reduces the force of impact on the player's hand principally because __________.
A) the velocity of the hand is reduced.
B) the time of impact is decreased.
C) the momentum of impact is reduced.
D) the time of impact is increased.
E) none of the above
2. Two gliders having the same mass and speeds move toward each other on an air track and stick together.
After the collision the velocity of the gliders is __________.
A) twice the original velocity.
B) There is not enough information to say.
C) one half the original velocity.
D) zero.
E) the same as the original velocity.
3. A piece of putty moving with 1 unit of momentum strikes and sticks to a heavy bowling ball that is
initially at rest. After the putty sticks to the ball, both are set in motion with a combined momentum that is
__________.
A) Not enough information to say
B) more than 1 unit.
C) 1 unit.
D) less than 1 unit.
4. A 4-kg ball is thrown at 8 m/s. What is the ball's momentum? [32 kg m/s]
5. A 10-kg ball has a momentum of 55 kg m/s. What is the ball's velocity? [5.5 m/s]
6. A ball is moving at 8 m/s and has a momentum of 56 kg m/s. What is the ball's mass? [7 kg]
7. True/ False When two objects collide and completely bounce apart with no lasting deformation or
generation of heat, the collision is said to be elastic.
8. True/False When two objects collide and completely stick together, the collision is said to be inelastic.
9. True/False Automobile dashboards that are padded lengthen the time of impact in case of a collision.
10. A 5.0-kg blob of clay moving horizontally at 2.0 m/s has a head-on collision with a 6.0-kg blob of clay
that moves toward it at 1.0 m/s. What is the speed if the two blobs stuck together immediately after the
collision? [0.364 m/s]
11. A 0.215-kg hockey puck moving at 53 m/s is caught by a 70-kg goalie at rest. With what velocity does
the goalie slide on the ice after catching the puck? [0.162 m/s]
12. A 0.044 kg bullet strikes a 6.0-kg stationary wooden block and embeds itself in the block. The block and
bullet move together at 9.7 m/s. What was the original velocity of the bullet? [1332.427 m/s]
13. A 48 g bullet moving at 500 m/s strikes a 3.2 kg wooden block. The bullet passes through the block,
leaving at 225 m/s. The block was at rest when it was hit. How fast is it moving when the bullet leaves?
[4.125 m/s]
14. A 0.75-kg ball traveling at 7.3 m/s rightward collides head-on with a 1.15-kg ball moving in the
opposite direction at a velocity of 13.0 m/s. The 0.75-kg ball moves away at 16 m/s leftward after the
collision. Find the velocity of the second ball. [2.196 m/s]
15. A 3500-kg truck moving rightward with a speed of 7 km/hr collides head-on with a 1200-kg car moving
leftward with a speed of 11 km/hr. The two vehicles stick together and move with the same velocity after
the collision. Determine the post-collision velocity of the car and truck. [0.668 m/s]
16. During a goal-line stand, a 80-kg fullback moving eastward with a speed of 8.6 m/s collides head-on
with a 110-kg lineman moving westward with a speed of 4.8 m/s. The two players collide and stick
together, moving at the same velocity after the collision. Determine the post-collision velocity of the two
players. [0.842 m/s]
79
PreAP Physics
Spring 2012
Extra Review Problems
Unit 8: Work, Energy, Power
1. If a neighbor pushes a lawnmower four times as far as you do but exerts only half the force, which
one of you does more work and by how much? [neighbor, twice]
2. A student slides a 0.75 kg textbook across a table, and it comes to rest after traveling 1.2 m. Given
the coefficient of kinetic friction between the book and the table is 0.34, find the book’s initial
speed. [2.8 m/s]
3. A pinball bangs against a bumper, giving the ball a speed of 42 cm/s. If the ball has a mass of 50.0 g,
what is the ball’s kinetic energy in Joules? [4.4 x 10-3 J]
4. A small 10.0 g ball is held to a slingshot that is stretched 6.0 cm. The spring constant is 200 N/m.
a. What is the elastic potential energy of the slingshot before it is released? [0.36 J]
b. What is the kinetic energy of the ball just after the slingshot is released? [0.36 J]
c. What is the ball’s speed at the instant it is released? [8.5 m/s]
d. How high does the ball rise if it is shot directly upward? [3.7 m]
5. A 50.0 kg student climbs 5.00 m up a rope at a constant speed. If the student’s power output is 200
W, how long does it take the student to climb the rope? How much work does the student do? [12.3
s; 2450 J]
6. Can the speed of an object change if the net work done on it is zero? Why? [No]
7. A person lifts a 4.5 kg cement block a vertical distance of 1.2 m. Determine the work done on the
block by the person. [53 J]
8. A plane designed for vertical takeoff has a mass of 8 x 103 kg. Find the net work done on the plane
as it accelerates upward at 1.0 m/s2 through a distance of 30.0 m after starting from rest. [2.4 x 105
J]
9. A flight attendant pulls her 70 N flight bag a distance of 253 m along a level airport floor at a
constant velocity. The force she exerts is 40 N at an angle of 52.0o above the horizontal. Find the
following:
a. The work she does on the flight bag [6230 J]
b. The work done by the force of friction on the flight bag [-6230 J]
c. The coefficient of kinetic friction between the flight bag and the floor. [0.352]
10. What is the kinetic energy of an automobile with a mass of 1250 kg traveling at a speed of 11 m/s?
[7.6 x 104 J]
11. In a circus performance, a monkey on a sled is given an initial speed of 4.0 m/s up a 25o incline. The
combined mass of the monkey and the sled is 20.0 kg, and the coefficient of kinetic friction between
the sled and the incline is 0.20. How far up the incline does the sled move? [1.4 m]
12. List the six types of energy and explain what each one is.
13. A child and sled with combined mass of 50.0 kg slide down a frictionless hill that is 7.34 m high. If
the sled starts from rest, what is its speed at the bottom of the hill? [12 m/s]
14. If an automobile engine delivers 50 hp of power, how much time will it take for the engine to do
6.40 x 105 J of work? (1 hp = 746 W) [17.2 s]
15. An 80 N box of clothes is pulled 20.0 m up a 30o ramp by a force of 115 N that points along the
ramp. If the coefficient of kinetic friction between the box and ramp is 0.22, calculate the change in
kinetic energy. [1200 J]
16. A 98.0 N grocery cart is pushed 12.0 m along an aisle by a shopper who exerts a constant horizontal
force of 40.0 N. If all frictional forces are neglected and the cart starts from rest, what is the grocery
cart’s final speed? [9.798 m/s]
17. A 0.60 kg rubber ball has a speed of 2.0 m/s at point A and kinetic energy of 7.5 J at point B.
Determine the following:
a. The ball’s kinetic energy at A [1.2 J]
b. The ball’s speed at B [5.0 m/s]
c. The total work done on the ball as it moves from A to B [6.3 J]
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PreAP Physics
Spring 2012
Extra Review Problems
18. Starting from rest, a 5.0 kg block slides 2.5 m down a rough 30.0o incline in 2.0 s. Determine the
following:
a. The work done by the force of gravity [61.25 J]
b. The work done by the normal force between the block and the incline. Why? [0 J]
19. A 2.5 x 103 kg car requires 5.0 kJ of work to move from rest to some final speed. During this time,
the car moves 25.0 m. Neglecting friction between the car and the road, find the following:
a. The final speed [2.0 m/s]
b. The horizontal force exerted on the car. [200 N]
20. A motor driven winch pulls a 50 kg student 5.00 m up a rope at a constant speed of 1.25 m/s.
a. How much power does the motor use in raising the student? [612.5 W]
b. How much work does the motor do on the student? [2.45 x 103 J]
21. A student with a mass of 80 kg runs up three flights of stairs in 12 seconds. The student has gone a
vertical distance of 8 meters.
a. Determine the amount of work done by the student to elevate his body to this height. [6272
J]
b. Determine the power exerted by the student. [522.667 W]
22. What amount of work can a 600-W electric drill do in 240 seconds? [1.44 x 105 J]
A 40-kg boy runs up the staircase to a floor 5.0 m higher in 7.0 seconds. What is his power output? [280 W]
81
PreAP Physics
Spring 2012
Extra Review Problems
Unit 9: Electrostatics
1. A negative charge of -6.0 µC exerts an attractive force of 65 N on a second charge 0.050 m away.
What is the magnitude of the second charge? [+3.009 x 10-6 C]
2. Two charges, q1 and q2, are separated by a distance, d, and exert a force, F, on each other. What new
force will exist if:
a. q1 is doubled? [x2]
b. q1 and q2 are cut in half? [1/4]
c. d is tripled? [1/9]
d. d is cut in half? [x4]
e. q1 is tripled and d is doubled? [x3/4]
3. Two electrons, each with a charge of -1.6 x 10-19 C, are separated by 1.5 x 10-10 m, the typical size of
an atom. What is the electric force between them? [1.024 x 10-8 N, repulsive]
4. A positive and negative charge, each of magnitude 1.5 x 10-5 C, are separated by a distance of 15 cm.
Calculate the force on the particles. [90 N, attractive]
5. Two negative charges of – 3.0 µC exert a repulsive force of 2.0 N on each other. Calculate the
distance that separates them. [0.201 m]
6. Three charges lie along the x-axis. One positive charge, q1 = 11.3 µC, is at the origin, and another
positive charge, q2 = 6.8 µC, is at x = 1.90 m. At what point on the x-axis must a negative charge, q3,
be placed so that the resultant force on it is zero? [1.070 m from q1]
7. A positive charge of 5.6 x 10-6 C is separated from a second positive charge of 7.2 x 10-6 C by 45 cm.
Calculate the electric force between the two particles. [1.792 N, repulsive]
8. A charge, q1 = 7.40 µC, is at the origin, and a second charge, q2 = -3.20µC, is on the x-axis 0.950 m
from the origin. Find the electric field at a point on the y-axis 0.630 m from the origin. [1.57 x 105
N/C at 83.23o]
9. An object, A, with +2.3 x 10-6 C charge, has two other stationary charges nearby. Object B, -4.1 x 10-6
C, is 0.080 m to the right. Object C, +6.1 x 10-6 C, is 0.12 m below. What is the net force on A? [15.898
N at 33.475o]
10. Two negative charges of -11.20 µC are separated by 0.750 m. What force exists between the
charges? [2.007 N]
11. A charge of +3.45 x 10-9 C is placed at the origin, and another charge of +5.6 x 10-9 C is placed at x=
2.3 m. Find the point between these two charges where a charge of +3.00 x 10-9 C should be placed
so that the net electric force on it is zero. [1.012 m from q1]
12. How far apart are two electrons, each with a charge of -1.6 x 10-19 C, if they exert a repulsive force of
2.30 N on each other? [1 x 10-14 m]
13. A force of 5.8 x 103 N exists between a positive charge of 7.30 x 10-4 C and a negative charge of -2.67
x 10-4 C. What distance separates the charges? [0.550 m]
82
PreAP Physics
Spring 2012
Extra Review Problems
14. Two identical point charges are separated by a distance of 7.0 cm and they repel each other with a
force of 11.0 x 10-5 N. What is the new force if the distance between the point charges is tripled?
[1.222 x 10-5 N]
15. Two point charges are separated by 120 cm. If one charge is + 14.3 µC and the other is -11.5 µC,
what is the force between them? [1.028 N, attractive]
16. A charge of 3.71 x 10-5 C is attracted by a second charge with a force of 465 N when the separation is
22.0 cm. Calculate the size of the second charge. [-6.740 x 10-5 C]
17. A charge q1 of -6.34 x 10-9 C and a charge q2 of -2.16 x 10-9 C are separated by a distance of 120.0 cm.
Find the equilibrium position for a third charge of +11.0 x 10-9 C. [0.758 m from q1]
18. A charge q1 of -6.82 x 10-9 C and a charge q2 of charge -5.70 x 10-9 C are separated by a distance of
85.0 cm. Where could a third charge be placed so that the net electric force on it is zero? [0.444 m
from q1]
19. A charge q1 = +8.15 µC is at the origin, and a charge q2 = -3.70 µC is on the x-axis 0.52 m from the
origin. Find the electric field strength at point P, which is on the y-axis 0.61 m from the origin.
[1.613 x 105 N/C at 77.979o]
20. A charge q1 = +11.9 µC is at the origin, and a charge q2 = -10.2 µC is on the x-axis 0.11 m from the
origin. Find the electric field strength at point P, which is on the y-axis 0.81 m from the origin.
[3.270 x 104 N/C at 55.528o]
21. Explain how you can identify how an object is charged? What makes each way unique? If possible,
draw an example situation or give examples.
Charging by friction:
Charging by contact:
Charging by induction:
Charging by polarization:
22. Draw the electric field lines for the following situations:
a. 1 positive particle
+
b. 1 positive and 1 negative particle
c. 2 positive charges
d. 1 negative charge
+
-
+
+
-
23. Calculate the magnitude and direction of the electric field strength at a point 0.04 m from a -45 μC
charge. [2.53 x 108 N/C, towards the particle]
83
PreAP Physics
Spring 2012
Extra Review Problems
Unit 10: Electrical Energy/Capacitance/Current/Power
1. A uniform electric field with a magnitude of 345 N/C is directed in the positive x direction. A 10.1 µC
charge moves from the origin to a point 54.0 cm to the right of origin. What is the change in electrical
potential energy of the system? [-1.88 x10-3 J]
2. Two charges are located along the x-axis. One has a charge of 80.2 µC, and the second has a charge of 13.8 µC. If the electrical potential energy associated with the pair of charges is 0.075 J, what is the distance
between the charges? [132.811 m]
3. A point charge of 11.1 x 10-9 C is located at the origin. A positive charge of 4.3 x 10-9 C is brought in from
infinity to a point such that the electrical potential energy associated with the two charges is 7.16 x 10-7 J.
How far apart are the charges at this time? [0.600 m]
4. Find the potential difference between a point infinitely far away and a point 0.25 m from a proton with
charge, 1.6 x 10-19 C. [5.76 x 10-9 V]
5. In a particular television tube, the beam current is 75.0 µA. How long does it take for 6.3 x 1012 electrons
to strike the screen? One electron’s charge is -1.6 x 10-19 C. [0.0134 sec]
6. A steady current of 3.8 A flows in a wire for 5 minutes. How much charge passes through any point in the
circuit? [1140 C]
7. A calculator is rated at 0.21 W when connected to a 1.5 V battery. What is the resistance of this device?
[10.714 Ώ]
8. An electric heater is operated by applying a potential difference of 75.0 V across a nichrome wire of total
resistance 9.25 Ώ. Find:
a. the current in the wire [8.108 A]
b. the power rating of the heater. [608.1 W]
9. A 4.0 µF capacitor is connected to a 12 V battery. What is the magnitude of the charge on each plate of the
capacitor? [4.8 x 10-5 C]
b. How much electrical potential energy is stored in the capacitor? [2.88 x 10-4 J]
10. The compressor on an air conditioner draws 45.0 A when it starts up. If the start-up time is 0.75 s, how
much charge passes a cross-sectional area of the circuit in this time? [33.75 C]
11. A total charge of 11.0 mC passes through a cross-sectional area of nichrome wire in 4.2 s.
a. What is the current in the wire? [2.619 x 10-3 A]
b. If the number of charges that pass through the cross-sectional area during the given time interval triples,
what is the resulting current? [7.857 x 10-3 A]
12. A 1300 W electric toaster is operated on a household circuit of 120 V. What is the resistance of the wire
that makes up the heating element of the toaster? [11.077 Ώ]
13. A 5.6 µF capacitor is connected to a 12 V battery. What is the charge on each plate of the capacitor?
[6.72 x 10-5 C]
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PreAP Physics
Spring 2012
Extra Review Problems
b. If this same capacitor is connected to a 1.50 V battery, how much electrical potential energy is stored?
[6.3 x 10-6 J]
14. The current in a certain resistor is 0.62 A when it is connected to a potential difference of 120 V. What is
the current in this same resistor if:
a. the operating potential difference is 75 V? [0.388 A]
b. the operating potential difference is 135 V? [0.698 A]
15. Assuming electrical energy costs $0.12 per kWh, calculate the cost of running each of the following
appliances for 24 hours if 120 V is supplied to each:
a. a 95 W stereo. [$0.27]
b. an electric oven that draws 32.0 A of current. [$11.06]
c. a television with a resistance of 76Ώ. [$0.54]
16. A 12 V battery is connected to a device and 24mA of current flows through it. If the device obeys Ohm’s
law, how much current will flow when a 24 V battery is used? [0.048 A]
17. The damage caused by an electric shock depends on the current flowing through the body; 1mA can be
felt; 5 mA is painful. Above 15 mA, a person loses muscle control, and 70 mA can be fatal. A person with dry
skin has a resistance from one arm to the other of about 1 x 105 Ώ. When skin is wet, the resistance drops to
about 5 x 103 Ώ.
a. What is the minimum voltage placed across the arms that would produce current that could be felt by a
person with dry skin? [100 V]
b. What effect would the same voltage have if the person had wet skin? [0.02 A] (0.015 A causes loss of
muscle control!)
c. What would be the minimum voltage that would produce a current that could be felt when the skin is
wet? [5 V]
18. Both a 3.3 µF and a 6.8 µF capacitor are connected across a 15 V potential difference. Which capacitor
has a greater charge? What is it? [6.8 µF capacitor; 1.02 x 10-4 C]
19. A capacitor is connected to a 45.0 V source contains 90 µC of charge. What is its capacitance? [2 x 10-6 F]
20. If you have a parallel-plate capacitor with a capacitance of 1.50 pF and a plate separation of 1.8 mm,
what would be the required surface area of each plate? [3.05 x 10-4 m2]
85
PreAP Physics
Spring 2012
Extra Review Problems
Unit 11: Circuits and Magnetism
1. A 10 Ώ resistor, a 20 Ώ resistor and a 5 Ώ resistor are connected in series across a 90 V battery.
a. What is the equivalent resistance of the circuit? [35 Ώ]
b. What is the current in the circuit? [2.571 A]
2. A 120 Ώ resistor, a 60 Ώ resistor and a 40 Ώ resistor are connected in parallel and placed across a
potential difference of 12 V.
a. What is the equivalent resistance of the circuit? [20 Ώ]
b. What is the current through the entire circuit? [0.6A]
c. What is the current through each branch of the parallel circuit? [0.1 A, 0.2 A, 0.3 A]
3. A wire 115 m long is at right angles to a uniform magnetic field. The field has a magnetic field streng
strength of
5.0 x 10-5 T. The current through the wire is 400 A. Find the magnitude of the force. [2.3 N]
4. A wire 0.10 m long carries a current of 5.0 A. The wire is at right angles to a uniform magnetic field. The
force on the wire is 0.20 N. What is the mag
magnitude of the magnetic field? [0.40 T]
5. A beam of electrons (q = 1.6 x 10-19 C) travels at 3.0 x 106 m/s through a 0.04 T uniform magnetic field.
The beam is at right angles to the magnetic field. What is the magnitude of the force acting on each
electron? [1.92 x 10-14 N]
6. A wire 0.50 m long carrying a current of 8.0 A is at right angles to a uniform magnetic field. The force on
the wire is 0.40 N. What is the strength of the magnetic field? [0.10 T]
7. A certain strand of miniature lights contains 35 bulbs wired in series, with each bulb having a resistance
of 15 Ώ. What is the equivalent resistance when three such strands are connected in parallel across a
potential difference of 120.0 V? [175 Ώ]
8. Three resistors with values of 28 Ώ, 58 Ώ, 22 Ώ, respectively, are connected in series. What is their
equivalent resistance? [108 Ώ]
9.Three
Three resistors with values of 15 Ώ, 41 Ώ, 58 Ώ, respectively, are connected in parallel. What is their
equivalent resistance? [9.259Ώ]
10.An electron moves north at a velocity of 8.4 x 104 m/s and has a magnetic force of 3.0 x 10–18 N exerted
on it. If the magnetic field points upward, what is the magnitude of the magnetic field? What is the direction
of the force? [2.2 x 10-4 T]
11. Draw a schematic
chematic diagram that contains one battery, two resistors, one capacitor, and one closed
switch.
12. What is the equivalent resistance for the resistors in the figure to
right? [10 Ώ]
86
PreAP Physics
Spring 2012
Extra Review Problems
13. Three resistors connected in parallel have individual values of 4.0 Ώ, 6.0 Ώ, and 10.0 Ώ, as shown above.
If this combination is connected in series with a 12.0 V battery and a 2.0 Ώ resistor,
a. what is the equivalent resistance in the circuit? [3.935 Ώ]
b. What is the current in and the potential differen
difference
ce across the 10.0 Ώ resistor? [0.590 A, 5.902 V]
14. A proton moves north at a velocity of 1.6 x 104 m/s and has a magnetic force of 1.6 x 10–18 N exerted on
it. If the magnetic force is to the east, what is the magnitude and direction of the magnetic field?
fie [6.25 x 10–4
T, upward]
15. If the potential difference across a pair of batteries used to power a flashlight is 6.0 V, what is the
potential difference across the flashlight bulb? [6.0 V]
16. In the schematic diagram right,, will there be a current? Why
or why not? [No]
17. Find the direction of the force on an electron moving through the magnetic field
shown above. [upward]
18. The Figure right depicts a household circuit containing
several appliances and a circuit breaker attached to a 120
V source of potential difference.
a. Is the current in the toaster equal to the current in the
microwave?
b. Is the potential difference across the microwa
microwave equal to
the potential difference across the popcorn popper?
c. Is the current in the circuit breaker equal to the current
in all of the appliances combined?
left determine the
19. For the circuit shown in the figure left,
following:
a. the current
nt and potential difference across the 2 Ώ resistor
[1.714 A, 3.428 V]
b. the current and potential difference across the 12 Ώ resistor
[0.429 A, 5.142 V]
87
PreAP Physics
Spring 2012
Extra Review Problems
Unit 12: Simple Harmonic Motion and Waves
Make sure to study all of your notes, problems worked in class and on previous homeworks and be familiar
with what was done on lab days.
1. You want to know the height of the ceiling at the Museum of Natural Science. A pendulum is attached to
the ceiling which almost touches the floor and its period is 15 s. How tall is the ceiling? [55.85 m]
b. What is the frequency of the pendulum? [0.067 Hz]
2. The body of a 1400 kg car is supported on a frame by four springs. Two people riding in the car have a
combined mass of 160 kg. When driven over a pothole in the road, the frame vibrates with a period of
0.960 s. For the first few seconds, the vibration approximates SHM. Find the spring constant for a single
spring. [16706.36N/m]
b. If 2 more people get in the car so that the total mass of people is 315 kg, what is the period of vibration of
the car when it drives over the pothole? [1.01 s]
3. A pinball machine uses a spring that is compressed 5.8 cm to launch a ball. If the spring constant is 14.2
N/m, what is the force on the ball at the moment the spring is released? [0.824 N]
4. If a mass of 0.82 kg attached to a vertical spring stretches the spring 6.7 cm from its original equilibrium
position, what is the spring constant? [119.94 N/m]
5. A 0.78 kg mass attached to a vertical spring stretches the spring 0.15 m. What is the spring constant?
[50.96 N/m]
b. The mass-spring system is now placed on a horizontal surface and set vibrating. What is the period of the
vibration? [0.777 s]
6. The piano string tuned to middle C vibrates with a frequency of 264 Hz. Assuming the speed of sound in
air is 349 m/s, find the wavelength of the sound waves produced by the string. [1.322 m]
7. A tuning fork produces a sound with a frequency of 256 Hz and a wavelength in air of 1.22 m. What value
does this give for the speed of sound in air? [312.32 m/s]
b. What would be the wavelength of the wave produced by this tuning fork in water in which sound travels
at 1500 m/s? [5.86 m]
8. If the amplitude of a sound wave is increased by a factor of three, how does the energy carried by the
sound wave in a given time interval change? Why? [9 times]
9. A wave of amplitude 0.40 m interferes with a second wave of amplitude 0.22 m. What is the largest
resultant displacement that may occur? [0.62 m]
10. A stretched string fixed at both ends is 3.0 m long. What are three wavelengths that will produce
standing waves on this string?
b. Name at least one wavelength that would not produce a standing wave pattern and explain your answer.
88
PreAP Physics
Spring 2012
Extra Review Problems
Sound
1. Sound waves are ____________ waves.
a. longitudinal
b. transverse
c. compression
d. a & b
e. a & c
2. When a sound wave is graphed as a sine wave, the compressions correspond to the _______ on the sine
graph and the rarefactions correspond to the _________.
Use the following words for #3-4. high, low, spread apart, close together
3. Compressions are regions of ______ density, _______ pressure and the molecules are ___________.
4. Rarefactions are regions of ______ density, _______ pressure and the molecules are ___________.
5. The frequency of a sound wave can be defined as…
6. The range frequencies a human can hear is ______________.
7. Sound waves lower than 20 Hz are called ___________. List some examples of when this type of wave is
used.
8. Sound waves higher than 20,000 Hz are called _________. List some examples of when this type of wave is
used.
9. The higher the frequency, the ____________ the wavelength.
10. How are pitch and frequency related? Which one is subjective (perceived differently by individuals)?
Which one is objective (can be measured precisely)?
11. List in order of increasing speed of sound the 3 states of matter. Why does sound travel fastest through
the medium that it does?
12. How does the temperature of a gas medium affect the speed of sound?
13. Draw a representation of a spherical sound wave. Label the wave front, wavelength, source, and ray.
Draw the sine curve that corresponds to your diagram.
14. Explain how the Doppler Effect works including diagrams. How does the pitch change as an object
moves towards and away from a stationary observer? What are some examples of things that use the
Doppler Effect?
15. How is intensity related to distance from the source of sound? If the distance from the source were to
double, what would happen to the sound intensity?
16. At a maximum level of loudness, the power output of a 150-piece orchestra radiated as sound is 95 W.
What is the intensity of these sound waves to a listener who is sitting 20 m from the orchestra?
17. If the intensity of a person’s voice is 5.2 x 10-7 W/m2 at a distance of 1.2 m, how much sound power does
that person generate?
18. The softest sound human can hear is known as the ______________, while the loudest sound a human can
tolerate is known as the __________.
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19. An increase of 10 dB corresponds to a _________ of the volume.
20. If the intensity of a sound is multiplied by 10, there is an increase of _________ dB.
21. What is relative intensity? It is also referred to as the ________ level because relative intensity is
measured in ___________.
22. What is an example of forced vibration?
23. What is natural frequency?
24. Explain resonance. Give at least one example.
25. Why is our outer ear shaped the way it is?
26. What types of waves are produced on strings and in air columns of instruments?
27. The ____________ frequency is the lowest possible frequency of a standing wave.
28. In what situation can you hear ALL of the harmonics? In what situation can you only hear the ODD
harmonics?
29. Explain what is happening when you can hear beats.
30. When the decibel level goes from 30 dB to 60 db, how much louder does the noise seem? How much
greater is the intensity?
31. If the speed of sound is 344 m/s, what are the first three harmonics in a 0.75 m long pipe with both
ends open?
32. If the speed of sound is 340 m/s, what are the first three harmonics in a 1.5 m long pipe with one end
closed?
33. On a piano, the note E has a fundamental frequency of 320 Hz. What is the second harmonic of this
note? If the piano wire is 60 cm long, what is the speed of waves on the wire?
34. You have two tuning forks, one with a frequency of 345 Hz and a second with an unknown frequency. If
you can hear 6 beats per second, what frequency could the unknown tuning fork be?
35. Label the following graph of 2 tuning forks with slightly different frequencies. Include destructive
interference, constructive interference, loud, soft, in-phase, out of phase. What does this graph represent?
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Extra Review Problems
Unit 13: Light & Optics
Terms to know: (don’t have to write them out)
Electromagnetic wave
Focal length
Electromagnetic spectrum
Magnification
Diffuse reflection
Refraction
Specular reflection
Angle of refraction and how it changes as move
Law of reflection
from fast slow and slow fast
Flat mirror
Index of refraction
Concave mirror
Converging lens
Convex mirror
Diverging lens
Real image
Polarization
Virtual image
Color
1. What is the frequency of an electromagnetic wave with a wavelength of 1.0x 105 m, if the wave is
traveling at 3 x 108 m/s? [3000 Hz]
2. If you are reading a book and you move 3 times as far away from the light source, how does the
brightness at the new distance compare with that at the old distance? [1/9 as bright]
3. A 6.0 cm pencil is placed upright 10 cm from a flat mirror. How are so and si related? How are ho and hi
related? Is the image real or virtual? Is the image upright or inverted?
4. A concave spherical mirror has a focal length of 15.0 cm. Locate the image of a pencil is placed upright 43
cm from the mirror. Find the magnification of the image. Is the image real or virtual? Is the image upright or
inverted? Reduced or enlarged? [23.04 cm, -0.536, R,I,R]
5. A concave mirror is designed so that a person 35.0 cm in front of it sees an upright image at a distance of
70 cm behind the mirror. What is the focal length of the mirror? What is the radius of curvature? Is the
image real or virtual? [70 cm, 140 cm, V]
6. A convex mirror with focal length of 45 cm forms a 0.80 cm tall image of a pencil at a distance of 20 cm
behind the mirror. What is the magnification of the image? Where is the pencil located? How tall is the
pencil? Is the image real or virtual? Is the image upright or inverted? [36 cm, 0.556, 1.489 cm, V,U]
7. A convex mirror with focal length of 43 cm forms an image of a bottle at a distance of 22 cm behind the
mirror. If the height of the image is 8.5 cm, where is the object located and how tall is it? What is the
magnification of the image? Is the image real or virtual? Is the image inverted or upright? [45.05 cm, 0.488,
17.42 cm, V,U]
8. A light ray traveling through air strikes a smooth pond of water (nwater = 1.333) at an angle of 35o to the
normal. Find the angle of refraction. Sketch a picture of the situation. [25.49o]
9. A ray of light traveling in water (nwater = 1.33), enters a slab of transparent material. The incoming ray
makes an angle of 52o with the normal and the refracted ray makes an angle of 61.2o with the normal. Find
the index of refraction of the transparent material. [1.199]
10. An object is placed 40 cm in front of a converging lens with a focal length of 12 cm. Find the image
distance and magnification. Is the image real or virtual? Upright or inverted? Enlarged or reduced? [17.143
cm, -0.429, R, I, R]
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Extra Review Problems
11. An object is placed 15 cm in front of a diverging lens with a focal length of 12 cm. Fins the image
distance and magnification. Is the image real or virtual? Upright or inverted? Enlarged or reduced? [-6.67
cm, 0.444, V,U,R]
12. An object is placed 5 cm from a converging lens with a focal length of 5 cm. Where is the image located?
Is the image real or virtual? Upright or inverted? Enlarged or reduced? [no image]
13. An object is placed 10 cm from a converging lens with a focal length of 5 cm. Where is the image
located? What is the magnification? Is the image real or virtual? Upright or inverted? Enlarged or reduced?
[10 cm, -1, R, I, same]
14.
15.
16.
17.
18.
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Extra Review Problems
19.
20.
22.
23
24.
25.
26
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Extra Review Problems
Unit 14: Thermodynamics
Temperature
1.) Convert each temperature to the other scale (Celsius to Kelvin and F, etc)
A. 4C to K and F
B. 4K to C and F
C. 4F to C and K
Heat
2.) How much heat in calories is needed to raise the temperature of 250 grams of water from 20oC to
40 oC? [5000 cal]
3.) How much heat in joules is needed to raise the temperature of 540 grams of water from 75 oC to
109 oC? [76818.24 J]
4.) How much heat is needed when 245 g of water is heated from 34oC to 90 oC?(Cp = 4.184 J/g oC)
[57404.48 ]
5.) When 400 calories of heat is lost from an object with a specific heat of 0.49 cal/g oC, the
temperature decreases from 110 oC to 50 oC. What is the mass of this object? [13.61 g]
6.) A chemist wants to raise the temperature of a 35 gram sample of water from 45 oC to 85 oC. How
much heat energy in calories is required to produce this change in temperature? (C = 1 cal/g oC)
[1400 cal]
7.) When 325 calories of heat is lost from an object with a specific heat of 0.26 cal/g oC, the
temperature decreases from 120 oC to 72 oC. What is the mass of this object? [26.04 g]
8.) Ernesto is knitting his wife a sweater in his 18 C air-conditioned living room with 0.30 m long
aluminum knitting needles, when he decides to knit outside in the 27 C air. How much will the
knitting needles expand when Ernesto takes them outside?
Heat Transfer
9.) What are the three methods of heat transfer and what type of medium do they work in?
10.) At what temperature is the density of water the greatest?
11.) Why do lakes and ponds freeze from the top down rather than from the bottom up?
12.) What is the role of” loose” electrons in heat conductors?
13.) Why does a piece of room temperature metal feel cooler to the touch than a piece of wood or
paper?
14.) How does the temperature of a gas change when it is compressed? When it expands?
15.) What is radiant energy?
16.) Why does a good absorber of radiant energy appear black?
17.) What is terrestrial radiation?
18.) What does it mean to say that the greenhouse effect is like a one-way valve?
Thermodynamics LAWS
19.) What is the meaning of thermodynamics?
20.) What happens to the internal energy of a system when work is done on it? What happens to its
temperature?
21.) If work is done adiabatically on a system, will the internal energy of the system increase or
decrease? If work is done by a system will the internal energy of the system increase or decrease
and why?
22.) What is the first law of thermodynamics?
23.) How does the second law of thermodynamics relate to the direction of heat flow?
24.) What three processes occur in the operation of every heat engine?
25.) What is the relationship between the second law of thermodynamics and entropy?
26.) Under what condition can entropy decrease?
27.) Give three examples of equipment that uses the principles of thermodynamic to operate.
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PreAP Physics
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Extra Review Problems
28.) What is an adiabatic process and give an example of one.
Efficiency:
29.) Calculate the ideal efficiency of a heat engine that takes in energy at 800K and expels heat at 300K
30.) Calculate the ideal efficiency of a ships boiler when steam comes out at 530K, pushes through a
steam turbine, and exits into a condenser at 290 K by circulating sea water.
31.) Calculate the ideal efficiency of a steam turbine that has a hot reservoir of 112C high pressure
steam and a sink at 27C
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Extra Problems
Unit 15: Quantum Nuclear Problems
1. Calculate the amount of energy released when 15 kg of plutonium is converted to energy in a fission
bomb. [1.35 x 1020J]
2. A nuclear bomb releases 63 10
of energy. Calculate the mass of the bomb that was converted to
energy. [7.0 x 10-4 kg, 0.7 g]
3. Jon puts on a pair of diffraction gratings glasses that he bought at a novelty shop and looks at a mercury
vapor street lamp that is 5.00 m away. He sees a yellow spectral line 1.16m on either side of the light
source. If the diffraction grating glasses have a slit separation of 2.49 x 10-6 m, what is the wavelength
Jon is looking at? [578 nm]
4. Houston radio station KKRW 93.7 has two transmitters that sit atop nearby buildings broadcasting a
wave that is 214 m long. As Kiesha drives down I-10 parallel to the two transmitters at a distance of
100.0m, she hears an increase in signal form the station every 30.0 m. How far apart are the two
transmitters? [713.3 m]
5. Compare the de Broglie wavelengths for a proton and an electron, each traveling at 3.00 x 107 m/s.
[p: 1.32 x 10-14m, e: 2.43x 10-11m]
6. The sun is a yellow star and emits most of its radiation in the yellow portion of the spectrum. If the
sun’s radiation peak at a frequency of 5.20 x 1014Hz, how much energy is emitted by one photon of this
visible light? [3.45x10-19J, 2.15eV]
7. The work function for three surfaces are: Wmercury = 4.5 eV, Wmagnesium = 3.85 eV, Wlithium = 2.30 eV.
a. At what threshold frequency are electrons liberated from each of these surfaces? [1.09 x 1015Hz,
9.30 x 1014 Hz, 5.55 x 1014 Hz)
b. What color light is corresponds to each? [275 nm – UV, 338 nm – UV, 541 nm - Yellow]
8. Shelby shines a red, helium-neon laser, with a wavelength of 633 nm, on a photo cell that has a work
function of 2.38 eV. What wavelength corresponds to the threshold frequency? [522 nm]
9. A classic physics demonstration involves placing a shiny zinc plate on a negatively charged electroscope
and shining UV light on the plate. If the work function of zinc is 4.31 eV and the wavelength of light is
250 nm. What is the kinetic energy of the photoelectrons ejected from the zinc plate? [0.66 eV]
10. Cobalt-60, used in radiation therapy for cancer patients has a half-life of 5.26 yr. A sample of cobalt 60
containing 5.00 x 1012 radioactive atoms sits in a lead case in the medical stockroom of Ben-Taub for
10.0 years.
a. What is the decay constant for cobalt-60? [0.132 / yr]
b. How many cobalt – 60 atoms remain? [1.33 x 1012 atoms]
11. Radioactive gold-198 is used as a tracer in liver tests in low level scans. Dr. R uses gold-198 in a scan on
Patient X who has been exhibiting signs of jaundice. A solution containing 3.00 x 109 gold – 198 atoms is
injected into his live and observed after 70.0 hr.
a. What is the decay constant of the gold if the half life is 2.70 days? [0.0107 / hr]
b. How many gold atoms are remaining after 72.0 hours? [1.39 x 109 atoms]
c. What is the activity of the gold-198 in Bq? [-4130 Bq]
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