Question 1

You are standing in a moving bus, facing forward, when you suddenly slide forward as the bus comes to an immediate stop. What force caused you to slide forward?

Accepted Answer

A)  the force due to friction between you and the floor of the bus 
B)  the normal force due to your contact with the floor of the bus 
C)  gravity 
D)  There is not a force causing you to slide forward.

Question 2

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

Accepted Answer

A)  perpendicular to the ramp. 
B)  down the ramp. 
C)  up the ramp. 
D)  vertically downward. 
E)  None of the above choices is correct.

Question 3

A 5.0-kg block and a 4.0-kg block are connected by a 0.6 kg rod, as shown in the figure.
The links between the blocks and the rod are denoted by A and B. A vertical upward force
of magnitude F of magnitude 150 N is applied to the upper block. What magnitude force
does each of the links A and B exert?

Accepted Answer

The answer of A 5.0-kg block and a 4.0-kg block...

Question 4

A person who normally weighs 700 N is riding in a rather swift elevator that is moving at a constant speed of 9.8 m/s. If this person is standing on a bathroom scale inside the elevator, what
Would the scale read?

Accepted Answer

A)  700 N 
B)  more than 700 N 
C)  less than 700 N 
D)  It could be more or less than 700 N, depending on whether the elevator is going up or down.

Question 5

What magnitude net force is required to accelerate a 1200-kg car uniformly from 0 m/s to 27.0 m/s in 10.0 s?

Accepted Answer

A)  3240 N 
B)  11800 N 
C)  4360 N 
D)  1620 N 
E)  444 N

Question 6

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

Accepted Answer

A)  slowing down and changing direction. 
B)  changing direction. 
C)  speeding up and changing direction. 
D)  slowing down. 
E)  speeding up.

Question 7

A  45.0-kg person steps on a scale in an elevator. The scale reads  460 N. What is the magnitude of the acceleration of the elevator?

Accepted Answer

A)   
B)   
C)   
D)   
E)

Question 8

A girl attaches a rock to a string, which she then swings counter-clockwise in a horizontal circle. The string breaks at point P in the figure, which shows a bird's-eye view (as seen from above).
Which path (A-E) will the rock follow?

Accepted Answer

A)  Path A 
B)  Path B 
C)  Path C 
D)  Path D 
E)  Path E

Question 9

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?

Accepted Answer

A)  
B)  
C)  
D)  
E)  None of these diagrams is correct.

Question 10

You push downward on a trunk at an angle 2  below the horizontal with a force of 750 N. If the trunk is on a flat surface and the coefficient of static friction between the surface and the trunk is
0)61, what is the most massive trunk you will be able to move?

Accepted Answer

A)  81 kg 
B)  73 kg 
C)  112 kg 
D)  93 kg

Question 11

The figure shows two boxes, with $m 1 > m 2$ that are on a level frictionless surface. We can apply a horizontal force $\overrightarrow { \mathrm { F} }$  either toward the right on $m 1$ or toward the left on $m _ { 2 }$ The magnitude of the force that the boxes exert on each other is

Accepted Answer

A)  larger if $\overrightarrow { \mathbf { F } }$ is applied toward the left. 
B)  the same in either case. 
C)  larger if $\overrightarrow { \mathbf { F } }$ is applied toward the right. 
D)  zero newtons in either case.

Question 12

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.

Accepted Answer

A) True 
 B)False

Question 13

A locomotive is pulling 9 freight cars, each of which is loaded with the same weight. The
mass of each loaded car is 37,000 kg, and we can neglect friction on these 9 cars. If the train
is accelerating forward at 0.81 m/s² on a level track, what is the tension in the coupling
between the second and third cars? (The car nearest the locomotive is counted as the first
car.)

Accepted Answer

The answer of A locomotive is pulling 9 freight cars,...

Question 14

In the figure, what does the spring scale read? The pulleys are ideal and the strings and scale are also massless.

Accepted Answer

A)  more than  19.6 N 
B)   0.00 N 
C)   0.50 N 
D)  exactly  2.0 N 
E)  exactly  1.0 N

Question 15

A 590-kg rocket is at rest on the launch pad. What upward thrust force is needed to
accelerate the rocket uniformly to an upward speed of 28 m/s in 3.3 s?

Accepted Answer

The answer of A 590-kg rocket is at rest on...

Question 16

In a shuffleboard game, the puck slides a total of 12 m on a horizontal surface before coming to rest. If the coefficient of kinetic friction between the puck and board is 0.10, what was the initial
Speed of the puck?

Accepted Answer

A)  3.8 m/s 
B)  48.5 m/s 
C)  4.8 m/s 
D)  4.3 m/s

Question 17

A tightrope walker walks across a  30-m long wire tied between two poles. The center of the wire is displaced vertically downward by  1.0 m when he is halfway across. If the tension in both halves of the wire at this point is  6294 N, what is the mass of the tightrope walker? Neglect the mass of the wire.

Accepted Answer

A)   74 kg 
B)   85 kg 
C)   43 kg 
D)   91 kg

Question 18

A 200-g hockey puck is launched up a ramp that is inclined at a  angle above the horizontal. The coefficients of static and kinetic friction between the puck and the ramp are  respectively, and the puck's initial velocity at the base is  3.8  m/s parallel to the sloping surface of the ramp. What speed does the puck have when it slides back down to its starting point?

Accepted Answer

The answer of A 200-g hockey puck is launched up...

Question 19

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?

Accepted Answer

A)  10.0 m/s 
B)  14.0 m/s 
C)  18.0 m/s 
D)  12.2 m/s 
E)  20.0 m/s

Question 20

A 2.8-kg tool can move on a perfectly smooth ramp that slants at  above the horizontal. What are the magnitude and direction of the acceleration of this tool if it is sliding (a) up the ram, (b) down the ramp?

Accepted Answer

The answer of A 2.8-kg tool can move on a...

Exam 4: Dynamics: Newtons Laws of Motion

You are standing in a moving bus, facing forward, when you suddenly slide forward as the bus comes to an immediate stop. What force caused you to slide forward?

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 person who normally weighs 700 N is riding in a rather swift elevator that is moving at a constant speed of 9.8 m/s. If this person is standing on a bathroom scale inside the elevator, what Would the scale read?

What magnitude net force is required to accelerate a 1200-kg car uniformly from 0 m/s to 27.0 m/s in 10.0 s?

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 45.0-kg person steps on a scale in an elevator. The scale reads 460 N. What is the magnitude of the acceleration of the elevator?

A girl attaches a rock to a string, which she then swings counter-clockwise in a horizontal circle. The string breaks at point P in the figure, which shows a bird's-eye view (as seen from above) . Which path (A-E) will the rock follow?

You push downward on a trunk at an angle 2 below the horizontal with a force of 750 N. If the trunk is on a flat surface and the coefficient of static friction between the surface and the trunk is 0) 61, what is the most massive trunk you will be able to move?

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.

In the figure, what does the spring scale read? The pulleys are ideal and the strings and scale are also massless.

A 590-kg rocket is at rest on the launch pad. What upward thrust force is needed to accelerate the rocket uniformly to an upward speed of 28 m/s in 3.3 s?

In a shuffleboard game, the puck slides a total of 12 m on a horizontal surface before coming to rest. If the coefficient of kinetic friction between the puck and board is 0.10, what was the initial Speed of the puck?

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 2.8-kg tool can move on a perfectly smooth ramp that slants at above the horizontal. What are the magnitude and direction of the acceleration of this tool if it is sliding (a) up the ram, (b) down the ramp?