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Midterm Exam Review
Honors Physics 2013-2014
Chapter 2
1. The driver of a car slams on the brakes as a truck approaches the car head-on. The driver is frozen
with horror for 4.20 s while the truck makes skid marks 62.4 m long. If the truck slows uniformly
at a rate of 5.60 m/s2, with what speed does the truck strike the car?
2. A model rocket is launched straight upward with an initial speed of 50.0 m/s. It accelerates a 2.00
m/s2 until its engines stop at an altitude of 150 m. (a) What is the maximum height reached by the
rocket? (b) How long after lift-off does the rocket reach its maximum height? (c) How long is the
rocket in the air?
3. In order to pass a physical education class at a university, a student must run 1.0 mi in 12 minutes.
After running for 10 minutes, she still has 500 yards to go. If her maximum acceleration is 0.15
m/s2, can she make it? If the answer is no, determine what acceleration she would need to be
successful.
4. A mountain climber stands at the top of a 50.0 m cliff that overhangs a calm pool of water. He
throws two stones vertically downward 1.0 s apart and observes that they cause a single splash.
The first stone has an initial velocity of 2.00 m/s. (a) How long after release of the first stone will
the two stones hit the water? (b) What initial velocity must the second stone have if they are to hit
simultaneously? (c) What will the velocity of each stone be at the instant they hit the water?
Chapter 3
5. A river flows due east at 1.50 m/s. A boat crosses the river from the south shore to the north shore
by maintaining a constant velocity of 10.0 m/s 35º northwest relative to the water. (a) What is the
velocity of the boat relative to the shore? (b) If the river is 500 m wide, how far downstream has
the boat moved by the time it reaches the north shore?
6. From the top of a tall building, a gun is fired
horizontally, with a bullet speed of 340 m/s.
The bullet put a hole in a window of another
building and hits the wall facing the window.
Determine the distances D and H, as shown in
the drawing, which locate the point where the
gun was fired. Assume that the bullet does not
slow down as it passes through the window.
7. A quarterback throws a football toward a receiver with an initial speed of 20 m/s, at an angle of
30º above the horizontal. At that instant, the receiver is 20 m from the quarterback. In what
direction and with what constant speed should the receiver run in order to catch the football at
the level at which it was thrown?
Answers: 1) 3.1 m/s; 2) 308.3 m, 8.5 s,16.4 s; 3) 66.3 s, yes; 4) 2.99 s, -15.4 m/s, -31.3 m/s, -34.9 m/s; 5) 8.81
@ 139º, 582.8 m; 6) 864 m, 32.1 m; 7) 7.52 m/s away; 8) 22.9 m/s, 207 m, 360 m; 9) 286.4 N; 10) 3.3 m/s2; 11)
236N, 118N; 12)6.53 m/s2; 13) 30.7º, 0.843 N; 14) 997 N, 796 N;15) 17.1 m/s; 16) 2.92 s; 17) 0.13; 18) 187.5
m, 14.8 m/s, 63.5 m/s; 19) 10 m/s; 20) 150 J, 7 m/s; 21)13.5m, 39.8 m; 22)all GPE, GPE + KE, 2.5 m
8. The determined coyote is out once more to try to capture the
elusive roadrunner. The coyote wears a new pair of Acme power
roller skates, which provide a constant horizontal acceleration of
15 m/s2. The coyote starts off at rest 70 m from the edge of a cliff
at the instant the roadrunner zips by in the direction of the cliff’s
edge. (a) If the roadrunner moves with constant speed, determine
the minimum speed he must have in order to reach the cliff
before the coyote. (b) If the cliff is 100 m above the base of the
canyon, determine where the coyote lands in the canyon,
assuming the skates do not accelerate him horizontally once he is air-borne. (c) Repeat (b), except
assume the skates continue to accelerate him horizontally once airborne.
Chapter 4
9. A 55.0 kg skier is pulled up a 25.0 º slope at a constant velocity by a
tow bar. If the coefficient of kinetic friction between the skis and
snow is 0.120, find the magnitude of the force of the tow bar on the
skier.
10. Find the acceleration experienced by each of the two masses
shown in the diagram, if the coefficient of kinetic friction between
the 7.0-kg mass and the plane is 0.250.
11. Two blocks are fastened to the ceiling of an elevator, which accelerates
upwards at 2.00 m/s2. Find the tension in each rope.
12. Mass m1, 5.00 kg, resting on a frictionless horizontal
table is connected to a cable that passes over a pulley
and then is fastened to a hanging mass, m2 = 10.0 kg.
Find the acceleration of each mass and the
tension in the cable.
13. A van accelerates down a hill, going from rest to
30.0 m/s in 6.00 s. During the acceleration, a 100g toy hangs by a string from the vans ceiling. The
acceleration is such that the string remains
perpendicular to the ceiling. Determine (a) the
angle , and (b) the tension in the string.
Answers: 1) 3.1 m/s; 2) 308.3 m, 8.5 s,16.4 s; 3) 66.3 s, yes; 4) 2.99 s, -15.4 m/s, -31.3 m/s, -34.9 m/s; 5) 8.81
@ 139º, 582.8 m; 6) 864 m, 32.1 m; 7) 7.52 m/s away; 8) 22.9 m/s, 207 m, 360 m; 9) 286.4 N; 10) 3.3 m/s2; 11)
236N, 118N; 12)6.53 m/s2; 13) 30.7º, 0.843 N; 14) 997 N, 796 N;15) 17.1 m/s; 16) 2.92 s; 17) 0.13; 18) 187.5
m, 14.8 m/s, 63.5 m/s; 19) 10 m/s; 20) 150 J, 7 m/s; 21)13.5m, 39.8 m; 22)all GPE, GPE + KE, 2.5 m
14. Find the tension in each cable supporting the 600-N cat burglar.
Chapter 5: Circular
15. A car moves a speed v across a bridge made in the shape of a circular arc of radius r. What is the
lowest speed at which the occupants of the car feel weightless if the radius is 30.0 m?
16. A heavy ball rotates in a conical pendulum at the end of a 2.3 m long cable. If the radius is 0.9 m,
then what is the time for one rotation of the ball?
17. In a popular amusement part ride, a rotating cylinder of radius 3.00 m is
set in rotation at an angular speed of 5.00 rad/s. The floor then drops
away, leaving the riders suspended against the wall in a vertical
position. What minimum coefficient of friction between a rider’s clothing
and the wall is needed to keep the rider from slipping?
18. On a conical race track, cars race in circles
parallel to the ground with a speed of 34.0
m/s. (a) At what value of distance d should a
driver locate his car if he wishes to stay on a
circular path without depending on friction?
(b) If the coefficient of static friction is 0.60,
what is the minimum speed that the car can
move and stay in the same location? (c) If the
coefficient of static friction is 0.60, what is the
maximum speed that the car can move and
stay in the same location?
Answers: 1) 3.1 m/s; 2) 308.3 m, 8.5 s,16.4 s; 3) 66.3 s, yes; 4) 2.99 s, -15.4 m/s, -31.3 m/s, -34.9 m/s; 5) 8.81
@ 139º, 582.8 m; 6) 864 m, 32.1 m; 7) 7.52 m/s away; 8) 22.9 m/s, 207 m, 360 m; 9) 286.4 N; 10) 3.3 m/s2; 11)
236N, 118N; 12)6.53 m/s2; 13) 30.7º, 0.843 N; 14) 997 N, 796 N;15) 17.1 m/s; 16) 2.92 s; 17) 0.13; 18) 187.5
m, 14.8 m/s, 63.5 m/s; 19) 10 m/s; 20) 150 J, 7 m/s; 21)13.5m, 39.8 m; 22)all GPE, GPE + KE, 2.5 m
Chapter 6
19. The drawing shows a person who, starting from rest
at the top of a cliff, swings down at the end of a rope,
releases it, and falls into the water below. There are
two paths by which the person can enter the water.
Suppose he enters the water at a speed of 10.0 m/s
via path 1. How fast is he moving on path 2 when he
releases the rope at a height of 3.85 m above the
water? Ignore the effects of air resistance.
20. A net external force is applied to a 6.00 kg object that is
initially at rest. The net force component along the
displacement of the object varies with the magnitude of
the displacement as shown in the drawing.(a) How much
work is done by the net force? (b) What is the speed of
the object at s = 20.0 m?
21. A truck is traveling at 11.1 m/s down a hill when the
brakes on all four wheels lock. The hill makes an angle of
15º with respect to the horizontal. The coefficient of kinetic friction between the tires and the road
is 0.750.
a. How far does the truck skid before coming to a stop?
b. What maximum speed would allow the car to stop within the allowed acceleration
tolerance of acceleration of 6 g’s?
22. Look at the diagram showing two ramps of different
lengths, inclined at the same angle, θ=50º. The initial
speed of the identical blocks is 7.00 m/s.
a. When the block on the longer track reaches its
maximum height, is its final total mechanical
energy all kinetic energy, all potential energy,
or some of each?
b. When the block on the shorter track reaches
the top of its trajectory after leaving the track,
is its final total mechanical energy all kinetic energy, all potential energy, or some of each?
c. Which block is higher above the ground when it stops moving upward? Provide evidence.
23. In 2.0 minutes, a ski lift raises 4 skiers at constant speed to a height of 165 m. The average mass of
each skier is 65 kg. What is the average power provided by the tension in the cable pulling the lift?
Answers: 1) 3.1 m/s; 2) 308.3 m, 8.5 s,16.4 s; 3) 66.3 s, yes; 4) 2.99 s, -15.4 m/s, -31.3 m/s, -34.9 m/s; 5) 8.81
@ 139º, 582.8 m; 6) 864 m, 32.1 m; 7) 7.52 m/s away; 8) 22.9 m/s, 207 m, 360 m; 9) 286.4 N; 10) 3.3 m/s2; 11)
236N, 118N; 12)6.53 m/s2; 13) 30.7º, 0.843 N; 14) 997 N, 796 N;15) 17.1 m/s; 16) 2.92 s; 17) 0.13; 18) 187.5
m, 14.8 m/s, 63.5 m/s; 19) 10 m/s; 20) 150 J, 7 m/s; 21)13.5m, 39.8 m; 22)all GPE, GPE + KE, 2.5 m
24. An archer pulls the bowstring back for a distance of 0.470 m before releasing the arrow. The bow
and string act like a spring whose spring constant is 425 N/m. (a) What is the elastic potential
energy of the drawn bow? (b) The arrow has a mass of 0.0300 kg. How fast is it traveling when it
leaves the bow?
25. A rifle fires a 2.17x10^-2-kg pellet straight upward, because the pellet rests on a compressed
spring that is released when the trigger is pulled. The spring has a negligible mass and is
compressed by 8.28x10^-2 m from its unstrained length. The pellet rises to a maximum height of
6.51 m above its position on the compressed spring. Ignoring air resistance, determine the spring
constant.
Chapter 5: Gravitation
26. A satellite is in circular orbit around and unknown planet. The satellite has a speed of 1.7x10^6
m/s, and the radius of th orbit is 5.25x10^6m. A second satellite also has a circular orbit around
the same planet with a radius of 8.6x10^6m. What is the orbital speed of the second satellite?
27. Calculate the magnitude of the gravitational force exerted on a 425 kg satellite that is a distance of
two earth radii from the center of the earth. What is the magnitude of the gravitational force
exerted on the earth by satellite? Determine the magnitude of the satellite's acceleration. What is
the magnitude of the earth's acceleration?
28. Mars has a mass of 6.46 x 1023 kg and a radius of 3.39 x 106 m. What is the acceleration due to
gravity on Mars? And how much would a 66.0-kg person weigh on Mars?
Answers: 1) 3.1 m/s; 2) 308.3 m, 8.5 s,16.4 s; 3) 66.3 s, yes; 4) 2.99 s, -15.4 m/s, -31.3 m/s, -34.9 m/s; 5) 8.81
@ 139º, 582.8 m; 6) 864 m, 32.1 m; 7) 7.52 m/s away; 8) 22.9 m/s, 207 m, 360 m; 9) 286.4 N; 10) 3.3 m/s2; 11)
236N, 118N; 12)6.53 m/s2; 13) 30.7º, 0.843 N; 14) 997 N, 796 N;15) 17.1 m/s; 16) 2.92 s; 17) 0.13; 18) 187.5
m, 14.8 m/s, 63.5 m/s; 19) 10 m/s; 20) 150 J, 7 m/s; 21)13.5m, 39.8 m; 22)all GPE, GPE + KE, 2.5 m