Download Newton`s Laws MC test

Forces and Newton's Laws of Motion
Name_____________________________________
Date__________
1) In a collision between a huge SUV and a small hybrid car, the SUV exerts a larger force on
the hybrid than the hybrid exerts on the SUV.
A) True
C) It depends on whether the collision is a
B) False
head-on collision or a rear-end collision.
2) A box is placed on a table which rests on the floor. The box pushes on the table; the reaction
force to the box's push on the table is the table's push on the floor.
A) True
B) False
3) In order to get an object moving, you must push harder on it than it pushes back on you.
A) True
B) False
4) If the rockets of a spaceship in outer space (far from all gravity) suddenly lose power and go
off, the spaceship will gradually slow to a stop.
A) True
B) False
5) You are in a train traveling on a horizontal track and notice that a piece of luggage starts to
slide directly toward the front of the train. From this observation, you can conclude that this train
is
A) speeding up.
D) speeding up and changing direction.
B) slowing down.
E) slowing down and changing direction.
C) changing direction.
6) While flying horizontally in an airplane, you notice that a string dangling from the overhead
luggage compartment hangs at rest at 15° away from the vertical toward the front of the plane.
Using this observation, you can conclude that the airplane is
A) moving forward.
D) accelerating backward.
B) moving backward.
E) not accelerating because the string is at
C) accelerating forward.
rest.
7) An elevator suspended by a vertical cable is moving downward but slowing down. The
tension in the cable must be
A) greater than the weight of the elevator.
C) equal to the weight of the elevator.
B) less than than the weight of the elevator.
8) A crate is sliding down an inclined ramp at a constant speed of 0.55 m/s. The vector sum of all
the forces acting on this crate must point
A) down the ramp.
D) vertically downward.
B) up the ramp.
E) None of the above choices is correct.
C) perpendicular to the ramp.
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Forces and Newton's Laws of Motion
9) A golf club hits a golf ball with a force of 2400 N, sending the ball into the air. The force
exerted on the club by the ball must be less than 2400 N or else the ball would not have moved
forward.
A) True
C) The answer depends on whether the
B) False
golfer followed through with the swing.
10) A 75-N box rests on a perfectly smooth horizontal surface. The minimum force need to start
the box moving is
A) 75 N.
C) 750 N.
B) 7.5 N.
D) any horizontal force greater than zero.
11) The acceleration due to gravity is lower on the Moon than on Earth. Which one of the
following statements is true about the mass and weight of an astronaut on the Moon's surface,
compared to Earth?
A) Mass is less, weight is the same.
C) Both mass and weight are less.
B) Mass is the same, weight is less.
D) Both mass and weight are the same.
12) When a 45-kg person steps on a scale in an elevator, the scale reads a steady 480 N. Which
of the following statements must be true? (There could be more than one correct choice.)
A) The elevator is accelerating upward at a constant rate.
B) The elevator is accelerating downward at a constant rate.
C) The elevator is moving upward at a constant rate.
D) From the given information, we cannot tell if the elevator is moving up or down.
13) On its own, a tow truck has a maximum acceleration of 3.0 m/s2. What will be its maximum
acceleration when the truck is using a light horizontal chain to tow a bus of twice its own mass?
A) 2.5 m/s2
C) 1.5 m/s2
B) 2.0 m/s2
D) 1.0 m/s2
14) A car of mass 1100 kg that is traveling at 27 m/s starts to slow down and comes to a
complete stop in 578 m. What is the magnitude of the average braking force acting on the car?
A) 690 N
C) 410 N
B) 550 N
D) 340 N
15) A certain aircraft has a mass of 300,000 kg. At a certain instant during its landing, its speed
is 27.0 m/s. If the braking force is a constant 445,000 N, what is the speed of the airplane 10.0 s
later?
A) 10.0 m/s
D) 18.0 m/s
B) 12.2 m/s
E) 20.0 m/s
C) 14.0 m/s
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Forces and Newton's Laws of Motion
16) The figure shows an acceleration-versus-force graph for three objects pulled by wires. If the
mass of object 2 is 36 kg, what are the masses of objects 1 and 3?
A) 12 kg and 90 kg
B) 72 kg and 18 kg
C) 90 kg and 12 kg
D) 12 kg and 72 kg
Applying Newton's Laws
17) In the figure, a 10-lb weight is suspended from two spring scales, each of which has
negligible weight. Which one of the following statements about the readings in the scales is
true?
A) Each scale will read 5 lb.
B) The top scale will read zero, the lower scale will read 10 lb.
C) The lower scale will read zero, the top scale will read 10 lb.
D) Each scale will show a reading between one and 10 lb, such that the sum of the two is 10 lb.
However, exact readings cannot be determined without more information.
E) None of these is true.
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Forces and Newton's Laws of Motion
18) Two blocks, A and B, are being pulled to the right along a horizontal surface by a horizontal
100-N pull, as shown in the figure. 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
the upper block, A?
A)
D)
B)
E)
C)
19) Two blocks, A and B, are being pulled to the right along a horizontal surface by a horizontal
100-N pull, as shown in the figure. 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
the lower block, B?
A)
C)
D)
B)
E) None of these diagrams is correct.
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Forces and Newton's Laws of Motion
20) A push of magnitude P acts on a box of weight W as shown in the figure. The push is
directed at an angle θ below the horizontal, and the box remains a rest. The box rests on a
horizontal surface that has some friction with the box. The friction force on the box due to the
floor is equal to
A) P sin θ
B) P cos θ
C) 0
D) P cos θ + W
E) P + W
21) In the figure, what does the spring scale read? The pulleys are ideal and the strings and scale
are also massless.
A) exactly 2.0 N.
B) exactly 1.0 N
C) 0.50 N
D) 0.00 N
E) more than 19.6 N
22) Two objects of unequal masses, M and m (M > m), are connected by a very light cord passing
over an ideal pulley of negligible mass. When released, the system accelerates, and friction is
negligible.
Which one of the following free-body diagrams most realistically represents the forces acting on
the two objects in the moving system?
A)
B)
C)
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D)
Forces and Newton's Laws of Motion
23) A 200-N sled of slides down a frictionless hillside that rises at 37° above the horizontal.
What is the magnitude of the force that the surface of the hill exerts on the sled?
A) 200 N
D) 150 N
B) 120 N
E) 0 N
C) 160 N
24) A 10-kg sign is held by two ropes as shown in the figure. What is the tension on rope A?
A) 44 N
B) 69 N
C) 72 N
D) 88 N
E) 98 N
25) A 3.0-kg and a 5.0-kg box rest side-by-side on a perfectly smooth, level floor. A horizontal
force of 32 N is applied to the 3.0-kg box pushing it against the 5.0-kg box, and, as a result, both
boxes slide along the floor. How hard do the two boxes push against each other?
A) 12 N
D) 32 N
B) 20 N
E) 0 N
C) 24 N
26) A 3.0-kg mass and a 5.0-kg mass hang vertically at the opposite ends of a very light rope that
goes over an ideal pulley. If the masses are gently released, what is the resulting acceleration of
the masses?
A) 0.00 m/s2
D) 4.9 m/s2
B) 3.7 m/s2
E) 6.1 m/s2
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C) 2.5 m/s
27) The figure shows a 100-kg block being released from rest from a height of 1.0 m. It then
takes 0.53 s for it to reach the floor. What is the mass m of the block on the left? There is no
friction or mass in the pulley, and the connecting rope is very light.
A) 16 kg
B) 14 kg
C) 13 kg
D) 11 kg
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Forces and Newton's Laws of Motion
28) A policeman investigating an accident measures the skid marks left by a car on the horizontal
road. He determines that the distance between the point that the driver slammed on the brakes
(thereby locking the wheels) and the point where the car came to a stop was 28.0 m. From a
reference manual he determines that the coefficient of kinetic friction between the tires and the
road under the prevailing conditions was 0.300. How fast was the car going when the driver
applied the brakes?
A) 10.7 m/s
D) 32.9 m/s
B) 12.8 m/s
E) 45.7 m/s
C) 21.4 m/s
29) Jason takes off across level water on his jet-powered skis. The combined mass of Jason and
his skis is 75 kg (the mass of the fuel is negligible). The skis produce a forward thrust of 200 N
and have a coefficient of kinetic friction with water of 0.10. Unfortunately, the skis run out of
fuel after only 90 s. What is Jason's top speed?
A) 150 m/s
C) 24 m/s
B) 240 m/s
D) 90 m/s
30) A 50.0-kg block is being pulled up a 16.0° slope by a force of 250 N that is parallel to the
slope. The coefficient of kinetic friction between the block and the slope is 0.200. What is the
acceleration of the block?
A) 0.528 m/
D) 0.983 m/
B) 0.158 m/
E) 0.260 m/
C) 0.412 m/
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