Question 1

A box slides down a 25.0° slope under its own weight. The coefficient of kinetic friction between the box and the slope is 0.350. What is the acceleration of the box?

Accepted Answer

A)  1.03 m/s2 
B)  2.06 m/s2 
C)  1.22 m/s2 
D)  2.20 m/s2 
E)  2.44 m/s2

Question 2

A car moving at 10.0 m/s encounters a depression in the road that has a circular cross-section with a radius of 30.0 m. What is the normal force exerted by the seat of the car on a 60.0-kg passenger when the car is at the bottom of the depression?

Accepted Answer

A)  200 N 
B)  389 N 
C)  789 N 
D)  489 N 
E)  589 N

Question 3

FIGURE 6-13 
-Refer to Figure 6-13. Block A has a mass of 3.00 kg, block B has a mass of 5.00 kg and block C has a mass of 2.00 kg. The pulleys are ideal and there is no friction between block B and the table. What is the acceleration of the masses?

Accepted Answer

A)  0.981 m/s2 
B)  1.86 m/s2 
C)  2.94 m/s2 
D)  4.20 m/s2 
E)  4.71 m/s2

Question 4

A 55.0-kg box rests on a horizontal surface. The coefficient of static friction between the box and the surface is 0.300. What horizontal force must be applied to the box for it to start sliding along the surface?

Accepted Answer

The answer of A 55.0-kg box rests on a horizontal...

Question 5

A flatbed truck is carrying a 20.0-kg crate along a level road. The coefficient of static friction between the crate and the bed is 0.400. What is the maximum acceleration that the truck can have if the crate is to stay in place?

Accepted Answer

A)  3.92 m/s2 
B)  7.84 m/s2 
C)  8.00 m/s2 
D)  78.5 m/s2 
E)  196 m/s2

Question 6

A 50.0-kg block is being pulled up a 15.0° slope by a force of 300 N which is directed 30.0° above the slope. The coefficient of kinetic friction between the block and the slope is 0.200. What is the acceleration of the block?

Accepted Answer

A)  1.36 m/s2 
B)  0.158 m/s2 
C)  0.924 m/s2 
D)  0.520 m/s2 
E)  1.47 m/s2

Question 7

An object moving along a curved path with constant speed does not have a net force acting on it.

Accepted Answer

A) True 
 B)False

Question 8

Its more difficult to start moving a heavy carton from rest than it is to keep pushing it with constant velocity, because

Accepted Answer

A)  The normal force is greater when the carton is at rest. 
B)  μs k. 
C)  Initially, the normal force is not perpendicular to the applied force. 
D)  μk s. 
E)  μs = μk.

Question 9

FIGURE 6-13 
-Refer to Figure 6-13. Block A has a mass of 6.00 kg, block B has a mass of 4.00 kg and block C has a mass of 3.00 kg. The pulleys are ideal and there is no friction between block B and the table. What is the acceleration of the masses?

Accepted Answer

A)  0.981 m/s2 
B)  1.97 m/s2 
C)  2.74 m/s2 
D)  2.26 m/s2 
E)  0 m/s2

Question 10

A 600-kg car is going around a banked curve with a radius of 110 m at a speed of 24.5 m/s. What is the appropriate banking angle so that the car stays on its path without the assistance of friction?

Accepted Answer

A)  29.1° 
B)  13.5° 
C)  33.8° 
D)  56.2° 
E)  60.9°

Question 11

An object moves in a circular path at a constant speed. Compare the direction of the object's velocity and acceleration vectors.

Accepted Answer

A)  Both vectors point in the same direction. 
B)  The vectors point in opposite directions. 
C)  The vectors are perpendicular. 
D)  The question is meaningless, since the displacement is zero. 
E)  The question is meaningless, since the acceleration is zero.

Question 12

A 3.00-kg mass and a 5.00-kg mass hang vertically at the ends of a rope that goes over an ideal pulley. If the masses are released from rest, how long does it take for the 3.00-kg mass to rise by 1.00 m?

Accepted Answer

A)  0.407 s 
B)  0.735 s 
C)  0.815 s 
D)  1.81 s 
E)  0.903 s

Question 13

An ideal pulley changes the direction of the tension in a string without changing its magnitude.

Accepted Answer

A) True 
 B)False

Question 14

The coefficient of static friction is always larger than the coefficient of kinetic friction.

Accepted Answer

A) True 
 B)False

Question 15

FIGURE 6-9 
-A 22.0-kg crate is pulled along a horizontal floor by the ideal arrangement shown in 
Figure 6-9. The force F is 300 N. The coefficient of friction between the crate and the floor is 0.270. What is the acceleration of the crate?

Accepted Answer

A)  4.17 m/s2 
B)  6.57 m/s2 
C)  2.34 m/s2 
D)  4.85 m/s2 
E)  9.65 m/s2

Question 16

A flatbed truck is carrying a 20.0-kg crate down a sloping road inclined 15.0° below the horizontal. The coefficient of static friction between the crate and the bed is 0.400. What is the maximum acceleration that the truck can have if the crate is to stay in place?

Accepted Answer

A)  1.25 m/s2 
B)  0.625 m/s2 
C)  2.50 m/s2 
D)  3.16 m/s2 
E)  6.33 m/s2

Question 17

A 50.0-kg box is resting on a horizontal floor. A force of 250 N directed at an angle of 26.0° below the horizontal is applied to the box. What is the minimum coefficient of static friction between the box and the surface required for the box to remain stationary?

Accepted Answer

A)  0.441 
B)  0.654 
C)  0.375 
D)  0.866 
E)  0.406

Question 18

A 50.0-kg box is resting on a horizontal floor. A force of 250 N directed at an angle of 20.7° below the horizontal is applied to the box. The coefficient of kinetic friction between the box and the surface is 0.300. What is the acceleration of the box?

Accepted Answer

A)  1.21 m/s2 
B)  1.77 m/s2 
C)  2.84 m/s2 
D)  3.54 m/s2 
E)  5.14 m/s2

Question 19

The force of kinetic friction between two surfaces is independent of the area of contact between the surfaces.

Accepted Answer

A) True 
 B)False

Question 20

A 50.0-kg block is being pulled up a 13.0° slope by a force of 250 N which is parallel to the slope, but the block does not slide up the slope. What is the minimum value of the coefficient of static friction required for this to happen?

Accepted Answer

A)  0.115 
B)  0.566 
C)  0.654 
D)  0.359 
E)  0.292

Exam 6: Applications of Newtons Laws

A box slides down a 25.0° slope under its own weight. The coefficient of kinetic friction between the box and the slope is 0.350. What is the acceleration of the box?

A car moving at 10.0 m/s encounters a depression in the road that has a circular cross-section with a radius of 30.0 m. What is the normal force exerted by the seat of the car on a 60.0-kg passenger when the car is at the bottom of the depression?

FIGURE 6-13 -Refer to Figure 6-13. Block A has a mass of 3.00 kg, block B has a mass of 5.00 kg and block C has a mass of 2.00 kg. The pulleys are ideal and there is no friction between block B and the table. What is the acceleration of the masses?

A 55.0-kg box rests on a horizontal surface. The coefficient of static friction between the box and the surface is 0.300. What horizontal force must be applied to the box for it to start sliding along the surface?

A flatbed truck is carrying a 20.0-kg crate along a level road. The coefficient of static friction between the crate and the bed is 0.400. What is the maximum acceleration that the truck can have if the crate is to stay in place?

A 50.0-kg block is being pulled up a 15.0° slope by a force of 300 N which is directed 30.0° above the slope. The coefficient of kinetic friction between the block and the slope is 0.200. What is the acceleration of the block?

An object moving along a curved path with constant speed does not have a net force acting on it.

Its more difficult to start moving a heavy carton from rest than it is to keep pushing it with constant velocity, because

FIGURE 6-13 -Refer to Figure 6-13. Block A has a mass of 6.00 kg, block B has a mass of 4.00 kg and block C has a mass of 3.00 kg. The pulleys are ideal and there is no friction between block B and the table. What is the acceleration of the masses?

A 600-kg car is going around a banked curve with a radius of 110 m at a speed of 24.5 m/s. What is the appropriate banking angle so that the car stays on its path without the assistance of friction?

An object moves in a circular path at a constant speed. Compare the direction of the object's velocity and acceleration vectors.

A 3.00-kg mass and a 5.00-kg mass hang vertically at the ends of a rope that goes over an ideal pulley. If the masses are released from rest, how long does it take for the 3.00-kg mass to rise by 1.00 m?

An ideal pulley changes the direction of the tension in a string without changing its magnitude.

The coefficient of static friction is always larger than the coefficient of kinetic friction.

FIGURE 6-9 -A 22.0-kg crate is pulled along a horizontal floor by the ideal arrangement shown in Figure 6-9. The force F is 300 N. The coefficient of friction between the crate and the floor is 0.270. What is the acceleration of the crate?

A flatbed truck is carrying a 20.0-kg crate down a sloping road inclined 15.0° below the horizontal. The coefficient of static friction between the crate and the bed is 0.400. What is the maximum acceleration that the truck can have if the crate is to stay in place?

A 50.0-kg box is resting on a horizontal floor. A force of 250 N directed at an angle of 26.0° below the horizontal is applied to the box. What is the minimum coefficient of static friction between the box and the surface required for the box to remain stationary?

A 50.0-kg box is resting on a horizontal floor. A force of 250 N directed at an angle of 20.7° below the horizontal is applied to the box. The coefficient of kinetic friction between the box and the surface is 0.300. What is the acceleration of the box?

The force of kinetic friction between two surfaces is independent of the area of contact between the surfaces.

A 50.0-kg block is being pulled up a 13.0° slope by a force of 250 N which is parallel to the slope, but the block does not slide up the slope. What is the minimum value of the coefficient of static friction required for this to happen?