Download PHY 101 Final Exam Preparation Notes

PHY 101 Final Exam Preparation Notes
Major topics covered this semester
Constant velocity and constant acceleration motion Chapters (1 & 2)
Vectors (Chapter 3)
Forces (Chapter 4)
Newton’s Laws (Chapter 5)
Work and Energy (Chapter 10 & 11)
Oscillations (Chapter 14)
Waves (Chapter 15)
Magnetic fields and forces (Chapter 24)
Electromagnetic Induction (Chapter 25)
Quizzes and Exams this semester
Motion Graphs
Constant Acceleration
Vectors
Newton’s 2ND Law
Simple Harmonic Motion
Magnetic Forces and Flux
Exam #1
Exam #2
Types of Problems on the Final Exam (16 in total)
Constant velocity and constant acceleration motion graph (1)
Constant velocity and constant acceleration motion problems (2)
Free body diagram (1)
Newton’s 2ND Law problems (2)
Work and Energy problems (2)
Kinetic energy
Gravitational potential energy
Elastic potential energy
Simple harmonic motion problems (2)
Wave problem (2)
Magnetic fields and forces problems (2)
Electromagnetic Induction problems (2)
The Summary page for each chapter studied will be provided. However, the more formulas you know, the less
time you will spend looking them up. You will not have time to look every formula up. I recommend that you
memorize the formulas for constant acceleration motion, Newton’s 2nd Law and energy formula (Work, KE,
PEGrav, PESpring). That will leave only the formulas for SHM, Waves, Magnetic Forces, and Faraday’s Law that
need to be looked up.
PHY 101 Quiz#1: Motion Graphs and Constant Velocity Problems
Name_______________________________________
Date: 1/31/11
1. The position-time graph of a car driving east on the thruway is shown below.
90
x, miles
60
30
t, min
0
30
60
90
120
150
180
210
240
270
-30
-60
-90
Answer the questions that follow graph.
a. What is the car’s position after 2 hours of driving?
b. What is the car’s displacement Δx during the first 4 hours of travel?
c. During what time interval was the car’s speed the greatest?
d. What was the speed of the car between the first and second hour of travel?
e. What is the speed of the car at time equals 130 minutes?
f. What is the car’s final position relative to its initial position after the entire trip?
2. The velocity-time graph of a cheetah is represented below. Answer the questions that follow
300
30
v, m/s
20
10
t, s
0
30
60
90
120
150
180
a. What is the cheetah’s initial velocity?
b. What is the cheetah’s maximum velocity in km/hr?
c. What is the cheetah’s acceleration between 60 and 70 seconds?
d. What is the cheetah’s acceleration between 150 and 180 seconds?
e. What was the cheetah’s displacement between 60 and 180 seconds?
210
240
PHY 101 Quiz on constant acceleration
Name________________________________
07 Feb 2011
1. A speed skater moving across frictionless ice at 8.0 m/s hits a 5.0 meter wide patch of rough ice. She
slows steadily and then continues on at 6.0 m/s. What is her acceleration on the rough ice?
2. You are driving to the grocery store at 20 m/s. You are 110 m from an intersection when the light turns
red. Assume that your reaction time is 0.70 s and that your car brakes with constant acceleration.
a. How far are you from the intersection when you begin to apply the brakes?
b. What acceleration will bring you to rest right at the intersection?
c. How long does it take you to stop after you have applied the brakes?
d. Sketch the velocity-time graph of the car from the moment the light turns red to the time the car
comes to a complete stop.
PHY 101 Quiz on Vectors
Name_________________________
1) Find the x and y components of the following vectors:
A) 240 N at 330º
B) 15 m at 12º
C) 20 m/s2 at 90º
2) From the x and y components given, find the direction and magnitude of the resultant.
A) Fy = 120 N, Fx = 345 N
B) ax = -15 m/s2, ay = 12 m/s2
3) Add the three vectors below. Use the graphical method to show a picture of the addition of the vectors. Use
the mathematical method to obtain the magnitude and direction of the resultant vector. Angles are measured
counterclockwise from the x-axis.
A = 450 N at 20º, B = 25 N at 270º, C = 230 N at 70º
4) A soccer ball is kicked with a horizontal velocity of 11.3 m/s and a vertical velocity of 3.5 m/s. What is the
magnitude and direction of the ball's velocity?
5) A shot putter applies a force of 415 N to a shot at an angle of 37º. What are the horizontal and vertical
components of this force?
PHY 101 Quiz on Newton’s 2ND Law
Name_______________________________
Two angled ropes used to support the crate in the
right can withstand a tension of 1500 N before they
is the largest mass the ropes can support?
2/28/11
55
35
figure to the
break. What
Josh starts his sled, with a combined mass of 60 kg at the top of a 3.0 m high hill that has a constant slope of
25. Assume there is negligible friction on the slope.
3m
25
1. What is the distance down the slope from Josh’s starting point to the bottom of the hill?
2. List the forces acting on Josh as he accelerates down the slope.
3. Construct a free body diagram of the forces on Josh while he accelerates down the slope and then write
the force balance equations parallel to and perpendicular to the slope.
4. Determine the magnitude of the normal force and Josh’s acceleration down the incline.
5. When Josh reaches the flat at the bottom of the hill the sled experiences a frictional force of 30 N. How
far will he slide before coming to rest?
Quiz on SHM
Name_____________________________
1) A block oscillating on a spring has a maximum speed of 12 cm/s. What will the block’s maximum speed be if the amplitude of
the oscillation is tripled?
2) A young boy rides his bicycle between the rails of a railroad track where the railroad ties are evenly spaced. He notices that if he
rides slowly the amplitude of his oscillation as he rides over the ties is not too large. If he increases his speed to a certain value,
the oscillations become quite large. If he continues to increase his speed, his oscillations become smaller in amplitude as when he
rode slowly. Explain what is happening.
3) A spring has an unstretched length of 12 cm. A 100 g mass hanging from the spring stretches it to an equilibrium length of 25
cm.
a)
What is the value of the spring constant for the spring?
b) The mass is pulled down by hand to where the spring’s length is 35 cm. When it is released it begins to oscillate. What is
the amplitude of the oscillation?
c)
What is the frequency of the oscillation?
d) If this same spring & mass system were transported to Mars, where the acceleration due to gravity is about 1/3 that what it is
on Earth, how will the frequency of the oscillation change?
4) An air-track glider is attached to a spring. The glider is pulled to the right and released from rest at t = 0 s. It then oscillates with
a period of 1.25 s and a maximum velocity of 12 cm/s.
a)
What is the amplitude of the oscillation?
b) What is the glider’s position at t = 0.075 s?
5) Astronauts on the first trip to an asteroid take along a pendulum that has a period on Earth of 0.75 s. The period on asteroid turns
out to be 15.0 s. What is the free-fall acceleration on the asteroid?
6) Telephone signals are often transmitted over long distances by microwaves. What is the frequency of microwave radiation with a
wavelength of 5.7 cm?
7) In 2003, an earthquake in Japan generated waves that travel outward at 5.5 km/s. 220 km to the west, seismic instruments record
the arrival of the earthquake waves. The Earthquake waves have a frequency of 2.0 Hz and caused a ground maximum
acceleration of 0.21g.
a)
How much time elapsed between the earthquake and the detection of the waves by this seismometer?
b) What is the wavelength of the earthquake waves?
c)
What was the maximum amplitude of the ground shaking (displacement) as the wave passed the seismometer?
8) The image below represents the harmonics of a vibrating 120 cm long string. Assume the
frequency of vibration is 60 Hz
a)
What is the wave speed of the 3rd harmonic (N=3)?
1ST Physics 101 Exam: Motion and Vectors
Please answer all questions in the blue books provided. Work clearly.
The position-time graph of a kids on a go-cart driving on there street is shown below. Answer the questions
that follow graph.
90
x, meters
60
30
0
30
60
90
120
150
180
210
240
270
t, sec
-30
300
-60
-90
3.
a. What is the cart’s position after 3 minutes?
b. What is the car’s displacement Δx during the first 1.5 minutes of travel?
c. During what time interval was the car’s speed the greatest?
d. How does the does the speeds of the cart compare during the first 1.5 minutes and the second 1.5
minutes?
e. What is the speed of the car at time equals 280 seconds?
f. What was the total distance the go-cart travelled in the five minutes of operation? (Hint: not its
displacement but the total distance travelled.)
4. The velocity-time graph of a flea is represented below. Answer the questions that follow
3
v, m/s
2
1
t, s
0
.5
1
1.5
a. What flea’s initial velocity?
2
2.5
3
3.5
4
4.5
5
5.5
6
b.
c.
d.
e.
What is the flea’s acceleration between in the first 0.25 seconds?
What was the flea’s displacement in the first 1.0 seconds?
What was the flea’s total displacement in 6 seconds?
What was the flea’s average velocity over the time interval shown6 seconds
5. A light-rail train going from one station to the next on a straight section of track accelerates from rest at
0.9 m/s2 for 25 s. It then proceeds at constant speed for 1 km before slowing down at 2.0 m/s2 until it
stops at the station.
a. Sketch the velocity-time graph for the train’s trip between stations. Label as completely as you
can.
b. What is the distance between stations?
c. How much time does it take the train to go between stations?
6. A foot ball is kicked straight up into the air; it hits the ground 6.4 seconds later.
a. What was the greatest height reached by the ball? Assume it is kicked at ground level.
b. With what speed did it leave the kicker’s foot?
7. A field mouse trying to escape a hawk runs in a four legged pattern such that leg A is 10 meters south,
leg B is 4 meters west, leg C is 8 m north-east and the final leg D is 6 m north-west.
a. Represent the field mouse’s escape route graphically sketching each of the four displacement
vectors.

b. Write each of the field mouse’s displacement vectors in coordinate pairs (i.e. A = (?, ?))
c. Determine the magnitude field mouse’s net displacement.
d. In what direction does the field mouse end at relative to his staring point?
6. An airplane is flying due east at 600 mph. However the pilot is unaware that he flying in a strong jet stream
that has a speed of 150 mph and is directed 60 east of north. The true velocity of the airplane is the vector sum
of the planes velocity and the velocity of the jet stream. Determine the magnitude and direction of the plane’s
true velocity.
PHY 101 Exam 2, Newton’s 2ND and Energy Spring 2011
Complete all the problems below. Record your work and answers in the blue books provided you.
1. An F-16 Falcon fighter aircraft takes off from an expeditionary airfield as shown in the photo. List four
forces acting on the aircraft at the moment shown in the image. Air resistance is not negligible?
2. Very small forces can have tremendous effects on the motion of very small objects. Consider a single
electron, with a mass of 9.1 x 10-31 kg, subject to a single force equal to the weight of a penny.
a. If a penny has a mass of 3.1 grams, what is the magnitude of the force on the electron?
b. What is the acceleration of the electron?
c. How long would this force need to be applied to the electron for the electron to reach the speed
of light? Ignore any relativistic effects.
3. A golden retriever is on the back seat of your car as
a red light. The dog does not slide off the seat. Draw a
diagram of all the forces acting on the dog while you
stopping.
4. A 30 kg loudspeaker is suspended 2.5 meters below the
two cables that are each 30 from the vertical. What is the
the cables?
you stop for
free-body
are
ceiling by
tension in
5. A set of fuzzy dice are suspended from a long string from
rearview mirror. As you accelerate the dice hang at a 10
vertical. What is the acceleration of the car?
the
from the
6. A robotic arm on a Mars rover is found to lift a maximum
of 17 kg when operating during testing on the Earth.
large a mass could the arm lift when it arrives on Mars
the acceleration due to gravity is 3.76 m/s2?
mass
How
where
7. A 14 kg child goes down a straight slide inclined 38 above the horizontal. How large is the normal
force on the child?
8. In a time of 52 sec, José Villanueva (Spain) carried a 175 kg (385 lb) piano 5 meters across a floor and
then climbed a staircase (15 steps each 35 cm high) before sitting down to play at it for three minutes
on the set of El Show de los Réecords, Madrid, Spain on 5 December 2001.
Staircase is
not to scale
a. How much work did José do in carrying the piano to the foot of the stair case?
b. How much work did José do in carrying the piano up the stair case?
c. What was his average power output?
9. A 20 kg child is on a swing that hangs
m rope. What is her speed at the bottom of
she swings out 90?
from a 3.5
her arc if
10. Two identical cars brake identically to a stop. One car is travelling at v1 = 65 mph and the other car is
traveling at v2 = 85 mph. Using kinetic energy and work concepts, calculate how much greater the
stopping distance the faster car d2 is compared to the stopping distance d1 of the slower car.
11. A new event has been proposed for the Winter Olympics. An athlete will sprint 100 m, starting from
rest, and then leap onto a 20 kg bobsled. The person and sled slide down a 50-m-long ice-covered
ramp, sloped at 20, and into a spring with a carefully calibrated spring constant of 2,000 N/m. The
athlete who compresses the spring the farthest wins the gold medal. Isaac, who’s mass is 55 kg, has
been training for this event. He can reach a maximum speed of 15m/s in the 100 m dash. How far will
Isaac compress the spring?