Question 1

FIGURE 6-4 
-A 16-kg fish is weighed with two spring scales, each of negligible weight, as shown in Figure 6-4. What will be the readings on the scales?

Accepted Answer

A)  The bottom scale will read 16 kg, and the top scale will read zero. 
B)  The sum of the two readings will be 32 kg. 
C)  The top scale will read 16 kg, and the bottom scale will read zero. 
D)  Each scale will show a reading greater than zero and less than 16 kg, but the sum of the two readings will be 16 kg. 
E)  Each scale will read 8 kg.

Question 2

Pulling out of a dive, the pilot of an airplane guides his plane into a vertical circle. At the bottom of the dive, the speed of the airplane is 320 m/s. What is the smallest radius allowable for the vertical circle if the pilot's apparent weight is not to exceed 7.00 times his true weight?

Accepted Answer

A)  1740 m 
B)  1490 m 
C)  2240 m 
D)  228 m 
E)  41.7 m

Question 3

Consider a particle moving with constant speed such that its acceleration of constant magnitude is always perpendicular to its velocity.

Accepted Answer

A)  It is moving in a straight line. 
B)  It is moving in a circle. 
C)  It is moving in a parabola. 
D)  It is moving in a hyperbola. 
E)  None of the above is definitely true all of the time.

Question 4

FIGURE 6-15 
-A 20.0-gram mass is attached to a 120 cm-long string as shown in Figure 6-15. It moves in a horizontal circle with a constant speed of 1.50 m/s. What is the angle α?

Accepted Answer

A)  10.8° 
B)  13.5° 
C)  17.7° 
D)  24.6° 
E)  49.2°

Question 5

A flatbed truck is carrying a crate along a level road. The coefficient of static friction between the load and the bed is 0.40. The truck accelerates forward and the crate stays in its place on the truck bed. In what direction is the force that the bed exerts on the crate?

Accepted Answer

A)  forward 
B)  backward 
C)  toward the center of the road 
D)  There is no frictional force because the crate does not move with respect to the bed. 
E)  There is not enough information to answer this question.

Question 6

A 1000-kg car is moving at 30.0 m/s around a horizontal curve whose radius is 100 m. What is the magnitude of the frictional force required to keep the car from sliding?

Accepted Answer

A)  9000 N 
B)  9810 N 
C)  300 N 
D)  900 N 
E)  3000 N

Question 7

As a car drives with its tires rolling freely without any slippage, the type of friction acting between the tires and the road is

Accepted Answer

A)  static friction. 
B)  kinetic friction. 
C)  a combination of static and kinetic friction. 
D)  neither static nor kinetic friction, but some other type of friction. 
E)  It is impossible to tell what type of friction acts in this situation.

Question 8

A 50.0-kg block is being pulled up a 16.0° slope by a force of 250 N which 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?

Accepted Answer

A)  0.528 m/s2 
B)  0.158 m/s2 
C)  0.412 m/s2 
D)  0.983 m/s2 
E)  0.260 m/s2

Question 9

A 600-kg car is going around a curve with a radius of 120 m that is banked at an angle of 25.0° with a speed of 30.0 m/s. The coefficient of static friction between the car and the road is 0.300. What is the force exerted by friction on the car?

Accepted Answer

A)  1590 N 
B)  3430 N 
C)  7240 N 
D)  7820 N 
E)  795 N

Question 10

FIGURE 6-12 
-Two masses are connected by a string which goes over an ideal pulley as shown in Figure 6-12. Block A has a mass of 3.00 kg and can slide along a rough plane inclined 30.0° to the horizontal. The coefficient of kinetic friction between block A and the plane is 0.400. Block B has a mass of 2.77 kg. What is the acceleration of the blocks?

Accepted Answer

A)  0.392 m/s2 
B)  1.96 m/s2 
C)  3.12 m/s2 
D)  5.35 m/s2 
E)  0 m/s2

Question 11

FIGURE 6-10 
-A 10-kg sign is held by two ropes as shown in Figure 6-10. What is the tension on rope A?

Accepted Answer

A)  44 N 
B)  69 N 
C)  72 N 
D)  88 N 
E)  98 N

Question 12

State the condition for an object to be in translational equilibrium.

Accepted Answer

The answer of State the condition for an object to...

Question 13

Answer: A
Diff: 3 Var: 1 Page Ref: Sec. 6-4
-Two masses are connected by a string which goes over an ideal pulley as shown in Figure 6-12. Block A has a mass of 3.00 kg and can slide along a rough plane inclined 30.0° to the horizontal. The coefficient of static friction between block A and the plane is 0.400. Block B has a mass of 2.77 kg. What is the tension in the string?

Accepted Answer

A)  22.0 N 
B)  22.7 N 
C)  26.1 N 
D)  24.5 N 
E)  27.3 N

Question 14

In order to simulate weightlessness for astronauts in training, they are flown in a vertical circle. If the passengers are to experience weightlessness, how fast should an airplane be moving at the top of a vertical circle with a radius of 2.50 km?

Accepted Answer

A)  157 m/s 
B)  314 m/s 
C)  78.5 m/s 
D)  255 m/s 
E)  510 m/s

Question 15

A net horizontal force is required for a body to move in a horizontal circle.

Accepted Answer

A) True 
 B)False

Question 16

A 50.0-kg block is being pushed up a 15.0° slope by a force of 300 N which is directed 30.0° below 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)  0.164 m/s2 
B)  0.967 m/s2 
C)  1.20 m/s2 
D)  2.20 m/s2 
E)  0.528 m/s2

Question 17

For an object that travels at a fixed speed along a circular path, the acceleration of the object is

Accepted Answer

A)  larger in magnitude the smaller the radius of the circle. 
B)  in the same direction as the velocity of the object. 
C)  smaller in magnitude the smaller the radius of the circle. 
D)  in the opposite direction of the velocity of the object. 
E)  zero.

Question 18

A 600-kg car is going around a curve with a radius of 120 m that is banked at an angle of 20° with a speed of 24.5 m/s. What is the minimum coefficient of static friction required for the car not to skid?

Accepted Answer

A)  0.12 
B)  0.24 
C)  0.36 
D)  0.48 
E)  0.60

Question 19

FIGURE 6-6 
-Two identical masses are attached by a light string that passes over a small pulley, as shown in Figure 6-6. The table and the pulley are frictionless. The masses are moving

Accepted Answer

A)  with an acceleration less than g. 
B)  at constant speed. 
C)  with an acceleration greater than g. 
D)  with an acceleration equal to g. 
E)  with an acceleration that cannot be determined without additional information.

Question 20

A flatbed truck is carrying a 20.0-kg crate up a sloping road inclined 15.0° above 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)  0.625 m/s2 
B)  1.25 m/s2 
C)  2.50 m/s2 
D)  3.16 m/s2 
E)  6.33 m/s2

Exam 6: Applications of Newtons Laws

FIGURE 6-4 -A 16-kg fish is weighed with two spring scales, each of negligible weight, as shown in Figure 6-4. What will be the readings on the scales?