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SAINT PATRICK’S HIGH SCHOOL
PHYSICS 12 ADVANCED
JANUARY 2003 EXAM
Mrs. L. Clarke
Instructions:
1. READ each question very carefully. There are no marks for answering a question
not asked or for neglecting to answer a question.
2. Mark all answers directly on this paper. Use scrap paper if necessary, but it will
not be marked.
3. Scientific calculators and rulers are allowed.
4. Write down as much as you can for each question, but be concise. There are
partial marks for sections B and C.
5. In section B where there is choice, only complete the number of questions
indicated (1 / 2). If you do more than the required number of questions, your
answers will be marked in the order that they appear, and the leftover questions
will not be marked.
GOOD LUCK!
Name: ________________________________
Mark:
SECTION A: MULTIPLE CHOICE
Circle the correct answer. There is only one correct answer per question. If more than one answer
if circled or the response is illegible, it will be marked wrong. (1 mark each, 40 marks total)
1. From the top of a cliff 50 m high, an
object is thrown horizontally at a velocity
of 20 m/s. What time does it take for the
object to hit the ground below?
a. 2.3 s
b. 3.2 s
c. 5.1 s
d. 10 s
7. A 65 kg person is standing in an elevator
and on top of a scale. The scale reads 71
kg. What is the acceleration of the
elevator?
a. 21 m/s2 [up]
b. 0.90 m/s2 [up]
c. 21 m/s2 [down]
d. 0.90 m/s2 [down]
2. See the diagram below. The total energy
of the projectile at point 3 is
a. mgh
b. ½ mv12
c. ½ mv12 + mgh
d. ½ mv12 – mgh
8. The coefficient of friction between an
object and the ground is 0.32. What is the
acceleration of the object if the ground is
flat and no other horizontal forces act?
a. 0.32 m/s2
b. 3.1 m/s2
c. 1.8 m/s2
d. not enough information
3. See the diagram for #2. The kinetic
energy of the projectile at point 3 is
a. mgh
b. ½ mv12
c. ½ mv12 + mgh
d. ½ mv12 – mgh
4. A projectile is shot from a certain height
above the ground at a velocity of 7.3 m/s
[30 degrees up from horizontal]. How
long will it be before the projectile returns
to its original height?
a. 0.32 s
b. 0.74 s
c. 0.86 s
d. 7.3 s
5. A ball is thrown straight upwards at a
velocity of +12 m/s. It reaches its
maximum height and then begins its
descent. Which statement is true about the
ball while it is descending?
a. The ball has positive velocity and
positive acceleration.
b. The ball has negative velocity and
positive acceleration
c. The ball has negative velocity and
negative acceleration
d. The ball has positive velocity and
negative acceleration
6. When the ball in the previous question is
at its maximum height, it has
a. Non-zero velocity and non-zero
acceleration
b. Zero velocity and non-zero
acceleration
c. Zero velocity and zero acceleration
d. Non-zero velocity and zero
acceleration
9. A car is rounding a flat curve of radius 50
m with a speed of 20 m/s. The centripetal
force provided by friction is 1.2 104 N.
What is the mass of the car?
a. 500 kg
b. 1000 kg
c. 1500 kg
d. 2500 kg
10. A 0.50 kg mass is attached to the end of a
1.0 m string. The system is whirled in a
horizontal circular path. If the maximum
tension that the string can withstand is 350
N, what is the maximum speed that the
mass can have if the string is not to break?
a. 700 m/s
b. 26 m/s
c. 19 m/s
d. 13 m/s
11. Let the average orbital radius of a planet
be R. Let the orbital period of the planet
be T. Which of the following is constant
for all planets orbiting the same sun?
a. T/R
c. T2/R3
2
b. T/R
d. T3/R2
12. A car goes around a curve of radius r at a
constant speed of v. Then it goes around
another curve, of radius 2r and at a
constant speed of 2v. What is the
centripetal acceleration of the car as it
goes around the second curve, as
compared to on the first curve?
a. ½ as large
b. the same
c. twice as large
d. four times as large
13. The speed of Halley’s comet, while
traveling in its elliptical orbit around the
sun,
a. Is constant
b. increases as it nears the sun
c. decreases as it nears the sun
d. is zero at two points in its orbit
14. Europa is one of the moons of Jupiter. It
has an orbital radius 9.40 times the radius
of Jupiter. Its period is 85.2 hours.
Callisto, another of Jupiter’s moons, has
an orbital radius 26.4 times the radius of
Jupiter. What is Callisto’s period?
a. 1.70  102 hr
b. 2.39  102 hr
c. 4.01  102 hr
d. 1.61  105 hr
15. Which of the following can be used to
calculate the acceleration due to gravity
on any planet?
a.
Gmp/rp
b. Grp2/mp
c. Gmp/rp2
d. Grp2/mp2
16. The gravitational attractive force between
two masses is F. If the masses are moved
to half of their original distance, what is
the new gravitational attractive force?
a. F/4
c. F/2
b. 2F
d. 4F
17. Who was the first person to realize that
the planets move in elliptical orbits, and
not circular ones, around the sun?
a. Johannes Kepler
b. Isaac Newton
c. Albert Einstein
d. Mrs. Clarke
18. Does the centripetal force acting on an
object moving in a circle at constant speed
do work on the object?
a. Yes, since a force acts and the object
moves, and work is force times
distance.
b. Yes, since it takes energy to turn an
object.
c. No, because the object has constant
speed.
d. No, because the force and the
displacement of the object are always
perpendicular.
19. What is the period of a pendulum with a
length of 0.750 m?
a. 0.481 s
c. 1.74 s
b. 4.71 s
d. 5.44 s
20. A 2.0 kg mass is hung from a vertical
spring, extending the spring by 3.0 kg.
The force constant for this spring is
a. 650 N/m
c. 6.5 N/m
b. 67 N/m
d. 0.67 N/m
21. The period of oscillation for the system in
the previous question, once set in motion,
would be
a. 0.49 s
c. 110 s
b. 0.49 Hz
d. 110 Hz
22. The period of a pendulum’s oscillation on
the moon, compared to its oscillation on
Earth, would be
a. Smaller
b. Larger
c. The same
d. Not enough information
23. If a pendulum is displaced to a large initial
angle, its period, as compared to the
period with a small initial angle, would be
a. Smaller
b. Larger
c. The same
d. Not enough information
24. A spring-driven dart gun propels a 10 g
dart. Work is done on the dart by
exerting an average force of 20 N over a
distance of 5.0 cm. With what speed
will the dart leave the gun, assuming the
spring has negligible mass?
a. 10 m/s
c. 14 m/s
b. 17 m/s
d. 20 m/s
25. You slam on the brakes of your car in a
panic, and skid a certain distance on a
straight, level road. If you had been
traveling twice as fast, what distance
would the car have skidded, if all other
conditions were the same?
a. 4 times farther
b. Twice as far
c.
2 times farther
d. Not enough information
26. Which of the following statements
correctly expresses the value of Fnet on
the box on the incline shown in the
diagram? ([up the ramp] is positive.)
a. -Fgsin - Ff +Fapp
b. -Fgcos - Ff +Fapp
c. Fapp + Ff – Fgsin
d. Fapp + Ff + Fgcos
27. A merry-go-round of radius 6.5 m is
rotating at an angular speed of 1.1 rad/s
when it begins to slow down at a rate of
0.49 rad/s2. How long will it take to
stop?
a. 0.54 s
c. 0.47 s
b. 2.2 s
d. 0.22 s
28. What is the linear speed of a point on
the outer edge of the merry-go-round in
the previous question?
a. 0.16 m/s
c. 5.9 m/s
b. 7.2 m/s
d. 9.8 m/s
29. What was the initial frequency of the
merry-go-round’s rotation in the
previous question?
a. 0.18 Hz
c. 0.91 Hz
b. 1.1 Hz
d. 0.14 Hz
30. A brick is moving at a speed of 3 m/s
and a pebble is moving at a speed of 5
m/s. If both objects have the same
kinetic energy, what is the ratio of the
brick’s mass to the pebble’s mass?
a. 25 to 9
b. 5 to 3
c. 1 to 6
d. 3 to 5
31. A lightweight object and a very heavy
object are sliding with equal speeds
along a level frictionless surface. They
both slide up the same frictionless hill.
Which rises to a greater height?
a. The heavy object, because it has
greater kinetic energy.
b. The lighter object, because it weighs
less.
c. They both slide to the same height.
d. Not enough information.
32. A torque of 230 mN acts on a point. At
what distance from the point should a
force of 99 N act in order to produce
static equilibrium at the point? Assume
no other forces act.
a. 0.43 m
c. 22 cm
b. 23 km
d. 2.3 m
33. Which combination of circumstances
would give the most torque on the
fulcrum of a seesaw?
a. A light person sitting far from the
fulcrum
b. A light person sitting close to the
fulcrum
c. A heavy person sitting far from the
fulcrum
d. A heavy person sitting close to the
fulcrum
34. A student standing on top of a building
throws a ball with a horizontal velocity
of 12 m/s. If the ball strikes the ground
45 m from the base of the building, how
high is the building?
a. 18 m
c. 37 m
b. 69 m
d. 140 m
35. A person drops a ball while standing on
a train moving at constant speed along a
horizontal track. What path does a
person at rest, off the train, see the ball
take?
a. A straight path down
b. A parabolic path with motion in the
direction opposite to that of the
train’s motion
c. A parabolic path with motion in the
direction of the train’s motion
d. A straight path angled forward in
the direction of the train’s motion
36. A 0.060 kg tennis ball, initially moving
at a speed of 12 m/s, is struck by a
racket causing it to rebound in the
opposite direction at a speed of 18 m/s.
What is the ball’s change in
momentum?
a. 0.36 kgm/s
c. 0.72 kgm/s
b. 1.1 kgm/s
d. 1.8 kgm/s
37. A railroad freight car, mass 15 000 kg,
is allowed to coast along a level track at
a speed of 2.0 m/s. It collides and locks
with a 50 000 kg second car, initially at
rest and with brakes released. What is
the speed of the two cars after they stick
together?
a. 0.46 m/s
c. 1.2 m/s
b. 0.60 m/s
d. 1.8 m/s
38. A 4.0 N force acts for 3.0 s on an object.
The force suddenly increases to 15 N
and acts for one more second. What
total impulse was imparted by these
forces to the object?
a. 12 Ns
c. 15 Ns
b. 16 Ns
d. 27 Ns
39. A ping pong ball moving East at a speed
of 4 m/s collides with a stationary
bowling ball. The ping pong ball
bounces back to the West, and the
bowling ball moves very slowly to the
East. Which object experienced the
greater magnitude of impulse during the
collision?
a. Neither, both experienced the same
magnitude of impulse.
b. The ping pong ball
c. The bowling ball
d. Not enough information
40. In an elastic collision, which of the
following statements is true?
a. Kinetic energy is conserved
b. Kinetic energy is gained
c. Kinetic energy is lost
d. None of the above
SECTION B: ESSAY QUESTION
Choose ONLY ONE of the following questions. Answer as completely as possible. If
necessary, use the back of a page for extra space, but please indicate if you do so. (10 marks)
1. Students set up a glider and some springs on an air track as shown.
The glider is pulled in one direction away from the equilibrium position and released. In a
sentence, describe what happens to each of the following in each case:
a) What happens to the period of the glider if the initial displacement of the glider is
increased? (2 pts)
b) What happens to the restoring force of the system as the glider moves farther from
the equilibrium position? (3 pts)
c) What happens to the speed of the glider as it moves farther from the equilibrium
position? (3 pts)
d) What happens to the period of the glider if the mass of the glider is increased? (2 pts)
OR
2. A metal ball is dropped at the same instant that a pellet is fired from a launcher as shown
in the diagram. The pellet leaves the muzzle of the launcher at a velocity of 53.0 m/s in
the direction of the metal ball.
In a few sentences,
a) describe the motion of the pellet,
(3 pts)
b) describe the motion of the ball (3 pts)
c) explain why the pellet and the ball will
collide (4 pts)
SECTION C: PROBLEMS: Answer all FOUR problems. Answer as fully as possible, using
correct units and significant figures, and demonstrating what you have learned in class. (10 marks
each, 40 marks total)
1.
The diagram shows two vehicles about to collide. Car A has a mass of 1500 kg and a speed of
50.0 km/hr in the direction indicated. Car B has a mass of 1200 kg and a speed of 40.0 km/hr in
the direction indicated. When they collide, the two cars remain stuck together.
a.
Draw a scale diagram showing the momentum of each vehicle before the impact, the total
momentum before impact, and the total momentum after the impact. (3 pts)
b.
Determine the final velocity of the combined mass after the impact. (4 pts)
c.
How does the total kinetic energy after the impact compare quantitatively to the total kinetic
energy before the impact? (i.e. give a percentage) (3 pts)
2.
Determine the coefficient of friction on the ramp in the diagram below, if the system moves at
constant, positive speed. Start with FBDs and show all necessary steps. (10 pts)
2.5 kg
8.5 
1.5 kg
3.
A 250 g ball is whirled in a horizontal circle on a 1.2 m long string. The tension in the string is
112 N. The string suddenly breaks and the ball becomes a projectile.
a.
Draw a diagram (or possibly 2 diagrams) of what will happen to the ball after the string
breaks, demonstrating what you know about BOTH circular motion AND projectiles. Include
a word explanation of each diagram. (3 pts)
b.
Determine the distance the ball would land from the center of the circle, if it was released at a
height of 1.8 m. (7 pts)
4.
In the diagram shown, the mass m is released from the height h and travels around the circular,
frictionless track. (a) Derive a formula for the minimum speed needed for the mass to stay on the
circle. (5 pts) (b) Derive a formula for the minimum height h from which the mass must be
released to travel around the circle, using what you found in part (a), in terms of only the radius r
of the circle. Show all steps clearly. (5 pts)
m
(not to scale)
h
r
SECTION D: BONUS QUESTION (2 pts possible)
Show all work on the back of this page. No work, no marks!
After a completely inelastic collision between two objects of equal mass, each having initial speed v,
the two objects move off together with speed v/3. What was the angle between their initial velocities?