Download Midterm Review Pt I.tst

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VECTORS
1) An airplane undergoes the following displacements: First, it flies 59 km in a direction 30° east of north. Next,
it flies 58 km due south. Finally, it flies 100 km 30° north of west. Using analytical methods, determine how
far the airplane ends up from its starting point. (For extra points, determine how many geese were sucked
into the turbines during the trip.)
A) 73 km
B) 68.7 km
C) 71.5 km
D) 74.4 km
E) 70.1 km
KINEMATICS
2) A car accelerates from 5.0 m/s to 21 m/s at a rate of 3.0 m/s2. How far does it travel while accelerating?
A) 207 m
B) 117 m
C) 41 m
D) 69 m
3) Acceleration is sometimes expressed in multiples of g, where g = 9.8 m/s2 is the acceleration due to the
earth's gravity. In a car crash, the car's velocity may go from 30 m/s to 0 m/s in 0.15 s. How many g's are
experienced, on average, by the driver?
A) 24 g
B) 20 g
C) 14 g
D) 26 g
Use Figure 2.1 to answer the following question(s).
Figure 2.1
4) The graph in Figure 2.1 shows the position of an object as a function of time. The letters H-L represent
particular moments of time. At which moment in time is the speed of the object equal to zero?
A) I
B) J
C) K
D) H
E) L
5) The graph in Figure 2.1 shows the position of an object as a function of time. The letters H-L represent
particular moments of time. At which moment in time is the speed of the object the highest?
A) L
B) H
C) K
D) I
E) J
6) A racquetball strikes a wall with a speed of 30 m/s and rebounds with a speed of 26 m/s. The collision takes
20 ms. What is the average acceleration of the ball during the collision?
A) 1300 m/s2
B) 2800 m/s2
C) zero
D) 200 m/s2
E) 1500 m/s2
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7) A child standing on a bridge throws a rock straight down. The rock leaves the child's hand at t = 0. Which of
the graphs shown here best represents the velocity of the stone as a function of time? (A child, on a bridge,
with a rock? Where's the supervision?)
A)
B)
C)
D)
E)
8) A train starts from rest and accelerates uniformly, until it has traveled 2.1 km and acquired a velocity of
24 m/s. The train then moves at a constant velocity of 24 m/s for 400 s. The train then slows down
uniformly at 0.065 m/s2, until it is brought to a halt. The distance traveled by the train while slowing down,
in km, is closest to:
A) 4.2
B) 4.0
C) 3.6
D) 3.8
E) 4.4
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9) Which of the following situations is impossible?
A) An object has velocity directed east and acceleration directed west.
B) An object has constant non-zero acceleration and changing velocity.
C) An object has zero velocity but non-zero acceleration.
D) An object has velocity directed east and acceleration directed east.
E) An object has constant non-zero velocity and changing acceleration.
PROJECTILES
Figure 3.1
10) A projectile is fired from the origin (at y = 0 m) as shown in Figure 3.1. The initial velocity components are
V0x = 940 m/s and V0y = 96 m/s. The projectile reaches maximum height at point P, then it falls and strikes
the ground at point Q. In Figure 3.1, the y-coordinate of point P is closest to:
A) 470 m
B) 940 m
C) 45,080 m
D) 45,550 m
E) 90,160 m
11) Two bullets are fired simultaneously, at a werewolf, parallel to a horizontal plane. The bullets have different
masses and different initial velocities. Which one will strike the plane first?
A) The slowest one.
B) They strike the plane at the same time.
C) The fastest one.
D) The heaviest one.
E) The lightest one.
12) A projectile, lets say a washing machine, is fired at time t = 0.0s, from point 0 at the edge of a cliff, with
initial velocity components of νox = 80 m/s and νoy = 200 m/s. The projectile rises, then falls into the sea at
point P. The time of flight of the projectile is 50.0 s.
Figure 3.2b
In Figure 3.2b, the x-coordinate of the projectile when its y-component of velocity equals 160 m/s upward is
closest to:
A) 330 m
B) 310 m
C) 290 m
D) 340 m
E) 280 m
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13) A boy throws a rock with an initial velocity of 3.13 m/s at 30.0° above the horizontal. How long does it take
for the rock to reach the maximum height of its trajectory?
A) 0.282 s
B) 0.441 s
C) 0.160 s
D) 0.313 s
NEWTON'S LAWS
14) A block is on a frictionless table, on earth. The block accelerates at 3.0 m/s2 when a 20 N horizontal force is
applied to it. The block and table are set up on the moon. The acceleration due to gravity at the surface of
the moon is 1.62 m/s2. The weight of the block on the moon is closest to:
A) 11 N
B) 5.5 N
C) 8.1 N
D) 6.8 N
E) 9.5 N
15) A person who normally weighs 200 pounds is standing on a scale inside an elevator. The elevator is moving
upwards with a speed of 7 m/s, and then begins to slow down at a rate of 5 m/s2. Before the elevator begins
to slow down, the reading of the scale is _________, and while the elevator is slowing down, the reading of
the scale is ________.
A) greater than 200 pounds, 0 pounds
B) greater than 200 pounds, 100 pounds
C) less than 200 pounds, 100 pounds
D) 200 pounds, 100 pounds
E) none of the above
Figure 5.8
16) In Figure 5.8, a block of mass M hangs in equilibrium. The rope which is fastened to the wall is horizontal
and has a tension of 38 N. The rope which is fastened to the ceiling has a tension of 59 N, and makes an
angle Θ with the ceiling. The angle Θ is
A) 40°
B) 33°
C) 65°
D) 45°
E) 50°
17) Jason takes off across level water on his jet-powered skis. The combined mass of Jason and skis is 75 kg (the
mass of the fuel is negligible). The skis have a thrust of 200 N and a coefficient of kinetic friction on water of
0.1. Unfortunately, the skis run out of fuel after only 90 s. Better luck next time J-bird! What is Jason's top
speed?
A) 24 m/s
B) 90 m/s
C) 150 m/s
D) 240 m/s
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18) As shown in Figure 4.3, a woman with a herniated L5 is straining to lift a large crate, without success. It is
too heavy. We denote the forces on the crate as follows: P is the upward force being exerted on the crate by
the person, C is the contact force on the crate by the floor, and W is the weight of the crate.
Figure 4.3
How are the magnitudes of these forces related, while the person is trying unsuccessfully to lift the crate?
Explain your reasoning.
A) P + C < W
B) P + C = W
C) P = C
D) P + C > W
19) Two bodies P and Q on a perfectly smooth horizontal surface are connected by a light cord. The mass of P is
greater than that of Q. A horizontal force F is applied to Q as shown in Figure 4.4, accelerating the bodies to
the right.
Figure 4.4
The magnitude of the force exerted by the connecting cord on body P will be
A) greater than F.
B) zero.
C) less than F but not zero.
D) equal to F.
20) A 10.0 kg block on a table is connected by a string to a 63 kg mass, which is hanging over the edge of the
table. Assuming that frictional forces may be neglected, what is the magnitude of acceleration of the 10.0 kg
block when the other block is released? (See Figure 5.12.)
Figure 5.12
A) 8.5 m/s2
B) 9.0 m/s2
C) 8.1 m/s2
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D) 7.5 m/s2
21) Two blocks, A and B, are being pulled to the right along a horizontal surface by a horizontal 100 N pull, as
shown in Figure 4.5. Both of them are moving together at a constant velocity of 2.0 m/s to the right, and both
weigh the same. Which of the figures below shows a correct free-body diagram of the horizontal forces
acting on upper block, A?
Figure 4.5
A)
B)
C)
D)
E)
22) Figure 5.10 shows a 4800 kg cable car descending a high hill. A counterweight of mass 4600 kg on the other
side of the hill aids the breaks in controlling the cable car's speed. The rolling friction of both the cable car
and the counterweight are negligible. How much braking force does the cable car need to descend at
constant speed?
Figure 5.10
A) 8100 N
B) 3500 N
C) 5800 N
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D) 980 N
Figure 5.14
Three blocks, connecting ropes, and a light frictionless pulley comprise a system, as shown. An external force P is applied
downward on block A. The system accelerates at the rate of 2.5 m/s2. The tension in the rope connecting block B and
block C equals 60 N.
23) In Figure 5.14, the external force P is closest to:
A) 190 N
B) 170 N
C) 250 N
D) 230 N
24) In Figure 5.14, the tension in the rope connecting block A and block B is closest to:
A) 300 N
B) 280 N
C) 260 N
D) 240 N
E) 210 N
E) 320 N
Figure 5.20
25) Blocks A and B of masses 10 kg and 7 kg, respectively, are connected by a rope, which passes over a light
frictionless pulley, as shown. The horizontal surface is rough. The coefficients of static and kinetic friction are
0.40 and 0.20, respectively. External forces P and Q act on block B, as shown. In Figure 5.20, force P equals 28
N. The maximum value of force Q, for which the system remains at rest is closest to:
A) 120 N
B) 140 N
C) 98 N
D) 110 N
E) 130 N
CIRCULAR MOTION, GRAVITY, SATELLITES
26) A person ties a rock to a string and whirls it around in a vertical circle such that sometimes the rock is going
straight upward and sometimes the rock is going straight down. She whirls the rock at the minimum speed
(constant in time) such that the string is always taut (no sag). When is the tension the highest?
A) It is highest when the rock is at the highest elevation.
B) It is highest when the rock is at the lowest elevation.
C) The tension is constant as the rock moves around in a circle.
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27) A 76 kg mass is connected to a nail on a frictionless table by a (massless) string of length 1.3 m. If the tension
in the string is 51 N while the mass moves in a uniform circle on the table, how long does it take for the mass
to make one complete revolution?
A) 8.1 s
B) 7.0 s
C) 8.7 s
D) 9.5 s
28) The reason an astronaut in an earth satellite feels weightless is that
A) this is a psychological effect associated with rapid motionand the astronaut is clinically insane.
B) the astronaut is at a point in space where the effects of the moon's gravity and the earth's gravity
cancel.
C) the astronaut is beyond the range of the earth's gravity.
D) the astronaut is falling.
E) the astronaut's acceleration is zero.
29) From what height off the surface of the Earth should an object be dropped to initially experience an
acceleration of 0.5400 g?
A) 2298 km
B) 5426 km
C) 1689 km
D) 2930 km
30) Suppose we want a satellite to revolve around the Earth 5 times a day. What should the radius of its orbit
be? (Neglect the presence of the moon.)
A) 2.11 × 10 7 m
B) 0.69 × 10 7 m
C) 7.22 × 10 7 m
D) 1.44 × 10 7 m
WORK, ENERGY, CONSERVATION OF ENERGY
31) A child does 350 J of work while pulling a box from the ground up to his tree house with a rope. The tree
house is 4.0 m above the ground. What is the mass of the box?
A) 5.3 kg
B) 6.7 kg
C) 8.9 kg
D) 8.0 kg
32) A traveler pulls on a suitcase strap at an angle 36° above the horizontal. If 555 J of work are done by the
strap while moving the suitcase a horizontal distance of 15 m, what is the tension in the strap?
A) 52 N
B) 46 N
C) 56 N
D) 37 N
33) 87 J of work are needed to stretch a spring from 1.4 m to 2.9 m from equilibrium. What is the value of the
spring constant?
A) 77 N/m
B) 39 N/m
C) 52 N/m
D) 27 N/m
34) You do 116 J of work while pulling your sister back on a swing, whose chain is 5.10 m long, until the swing
makes an angle of 32.0° with the vertical. What is your sister's mass?
A) 13.0 kg
B) 17.6 kg
C) 15.3 kg
D) 19.0 kg
35) A 1321 kg car climbs a 5.0° slope at a constant velocity of 80.0 km/h.(22.2 m/s) Assuming that air resistance
may be neglected, at what rate must the engine deliver energy to the drive wheels of the car? Express your
answer in kW.
A) 48 kW
B) 25 kW
C) 288 kW
D) 38 kW
36) If a ball is released from a window ledge, how fast will it be travelling when it reaches the ground, 43 m
below?
A) 0 m/s
B) 0.86 km/s
C) 58 m/s
D) 29 m/s
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37) A block slides down a frictionless inclined ramp. If the ramp angle is 17.0° and the length of it is 20.0 m, find
the speed of the block as it reaches the end of the ramp, assuming it started sliding from rest at the top.
A) 19.6 m/s
B) 114 m/s
C) 7.57 m/s
D) 10.7 m/s
38) Sue and Betti both ski straight down a hill, both starting from rest. Sue weighs more than Betti. Betti is
holding a grudge. Neglecting friction and wind resistance, which skier will be moving the fastest at the
bottom of the hill?
A) They will be moving with the same speed.
B) Sue
C) Betti
IMPULSE, MOMENTUM & CONSERVATION OF MOMENTUM
39) A 328 kg car moving at 19.1 m/s hits from behind another car moving at 13.0 m/s in the same direction. If
the second car has a mass of 790 kg and a new speed of 15.1 m/s, what is the velocity of the first car after
the collision?
A) 18.2 m/s
B) -14.0 m/s
C) 24.2 m/s
D) 14.0 m/s
40) A golf ball of mass 0.050 kg is at rest on the tee and has a velocity of 102 m/s immediately after being struck.
If the club and ball were in contact for 0.81 ms, what is the average force exerted on the ball?
A) 5.5 kN
B) 4.9 kN
C) 6.3 kN
D) 7.1 kN
41) A 1200 kg cannon fires a 100.0 kg cannonball at 35 m/s. What is the recoil velocity of the cannon? Assume
that frictional forces are negligible and the cannon is fired horizontally.
A) 35 m/s
B) 2.9 m/s
C) 3.5 m/s
D) 3.2 m/s
42) A steady horizontal force lasting for 2.10 s gives a 1.25 kg object an acceleration of 3.20 m/s2 on a frictionless
table. What impulse does this force give to the object?
A) 25.7 kg m/s
B) 4.00 kg m/s
C) 8.40 kg m/s
D) 2.63 kg m/s
E) 10.9 kg m/s
Figure 8.2
43) A block of mass m = 4.4 kg, moving on frictionless surface with a speed v i = 9.2 m/s, makes a perfectly
elastic collision with a block of mass M at rest. After the collision, the 4.4 kg block recoils with a speed of
v f = 2.5 m/s. In Figure 8.2, the mass M is closest to:
A) 12 kg
B) 5.6 kg
C) 4.4 kg
D) 21 kg
E) 7.7 kg
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Figure 8.5
44) An 8 g bullet is shot into a 4.0 kg block, at rest on a frictionless horizontal surface. The bullet remains lodged
in the block. The block moves into a spring and compresses it by 8.9 cm. The force constant of the spring is
1400 N/m. In Figure 8.5, the impulse of the block (including the bullet), due to the spring, during the entire
time interval in which block and spring are in contact is closest to:
A) 10 N · s
B) 8.3 N · s
C) 12 N · s
D) 13 N · s
E) 6.7 N · s
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