Question 1

One end of a rope is pulled with 100 N, while the opposite end also is pulled with 100 N. The tension in the rope is

Accepted Answer

A)  0 N.
B)  50 N.
C)  100 N.
D)  200 N.

Question 2

Harry pulls on the end of a spring attached to a wall. The reaction to Harry's pull on the spring is

Accepted Answer

A)  the wall pulling oppositely on the spring.
B)  the spring pulling on Harry.
C)  both the wall and the spring pulling on Harry.
D)  none of the above

Question 3

When a tennis racquet hits a ball,

Accepted Answer

A)  the racquet loses as much speed as the ball gains.
B)  the ball is set in motion with the same speed of the racquet upon contact.
C)  the ball hits the racquet.
D)  all of the above

Question 4

An archer shoots an arrow. Consider the action force to be the bowstring against the arrow. The reaction to this force is the

Accepted Answer

A)  combined weight of the arrow and bowstring.
B)  friction of the ground against the archer's feet.
C)  grip of the archer's hand on the bow.
D)  arrow's push against the bowstring.

Question 5

When a ball falls downward, it may have a net force

Accepted Answer

A)  equal to its weight.
B)  of zero.
C)  equal to its weight minus air drag.
D)  any of the above
E)  none of the above

Question 6

Your friend says that the heavyweight champion of the world cannot exert a force of 50 N on an isolated piece of tissue paper with his best punch. You

Accepted Answer

A)  agree that it can't be done.
B)  have reservations about this assertion.
C)  disagree, for a good punch easily delivers this much force.

Question 7

To say there is no such thing as only one force means

Accepted Answer

A)  there must also be a corresponding reaction force.
B)  other forces, perhaps not evident, are there.
C)  gibberish.

Question 8

If vertically falling rain makes slanted 45° streaks on the side windows of a moving car, the speed of the car

Accepted Answer

A)  is less than the speed of the falling drops.
B)  equals the speed of the falling drops.
C)  exceeds the speed of the falling drops.
D)  need more information

Question 9

When Nellie hangs suspended from a pair of ropes that are not vertical, the tension in each rope is

Accepted Answer

A)  less than half her weight.
B)  half her weight.
C)  more than half her weight.
D)  her weight.

Question 10

The airspeed of an airplane is 200 km/h. When it is caught in a 200-km/h crosswind, its speed across the ground below is

Accepted Answer

A)  0 km/h.
B)  200 km/h.
C)  283 km/h.
D)  400 km/h.
E)  1600 km/h.

Question 11

When a skateboarder pushes on a wall,

Accepted Answer

A)  an interaction occurs between the skateboarder and the wall.
B)  the wall pushes on the skateboarder.
C)  such a push couldn't happen unless the wall pushed on the skateboarder.
D)  all the above
E)  none of the above

Question 12

A pair of equal-length vectors at right angles to each other have a resultant. If the angle between the vectors is less than 90°, their resultant is

Accepted Answer

A)  less.
B)  the same.
C)  greater.

Question 13

Action and reaction pairs of forces

Accepted Answer

A)  always act simultaneously.
B)  may or may not act simultaneously.
C)  are independent of time.

Question 14

Two people, one twice as massive as the other, attempt a tug-of-war with 12 meters of rope on frictionless ice. After a brief time, they meet. The heavier person slides a distance of

Accepted Answer

A)  3 m.
B)  4 m.
C)  6 m.
D)  0 m.

Question 15

A pair of equal-length vectors at right angles to each other have a resultant. If the angle between the vectors is greater than 90°, their resultant is

Accepted Answer

A)  less.
B)  the same.
C)  greater.

Question 16

A 10-unit vector at 60° from the vertical has a vertical component with a magnitude

Accepted Answer

A)  less than 10 units.
B)  10 units.
C)  greater than 10 units.

Question 17

The lift experienced by a helicopter involves an action-reaction pair of forces between the

Accepted Answer

A)  helicopter blades and the air.
B)  mass of the helicopter and Earth's mass.
C)  weight of the helicopter and atmospheric pressure.
D)  motion of the helicopter relative to the ground below.
E)  any or all of the above

Question 18

A river 100 m wide flows due south at 1 m/s. A boat that goes 1 m/s relative to the water leaves the west bank. To land at a point due east of its starting point, the boat must be pointed

Accepted Answer

A)  northeast.
B)  east.
C)  southeast.
D)  nowhere-it can't be done.

Question 19

Two equal-size vectors at right angles to each other have a resultant that is

Accepted Answer

A)  equal to that of either vector.
B)  √2 the length of either vector.
C)  twice the length of either vector.

Question 20

Nellie Newton pulls her sled by a rope that is 45° to the horizontal. The horizontal and vertical components of force are

Accepted Answer

A)  equal in magnitude.
B)  each about 0.7 times the force she exerts on the rope.
C)  both of these
D)  neither of these

Exam 5: Newtons Third Law of Motion: Action and Reaction

Two people, one twice as massive as the other, attempt a tug-of-war with 12 meters of rope on frictionless ice. After a brief time, they meet. The heavier person slides a distance of

Correct AnswerverifiedShow Answer

The airspeed of an airplane is 200 km/h. When it is caught in a 200-km/h crosswind, its speed across the ground below is

Correct AnswerverifiedShow Answer

Your friend says that the heavyweight champion of the world cannot exert a force of 50 N on an isolated piece of tissue paper with his best punch. You

Correct AnswerverifiedShow Answer

A pair of equal-length vectors at right angles to each other have a resultant. If the angle between the vectors is greater than 90°, their resultant is

Correct AnswerverifiedShow Answer

A 10-unit vector at 60° from the vertical has a vertical component with a magnitude

Correct AnswerverifiedShow Answer

When a tennis racquet hits a ball,

Correct AnswerverifiedShow Answer

The lift experienced by a helicopter involves an action-reaction pair of forces between the

Correct AnswerverifiedShow Answer

A pair of equal-length vectors at right angles to each other have a resultant. If the angle between the vectors is less than 90°, their resultant is

Correct AnswerverifiedShow Answer

Nellie Newton pulls her sled by a rope that is 45° to the horizontal. The horizontal and vertical components of force are

Correct AnswerverifiedShow Answer

A river 100 m wide flows due south at 1 m/s. A boat that goes 1 m/s relative to the water leaves the west bank. To land at a point due east of its starting point, the boat must be pointed

Correct AnswerverifiedShow Answer

If vertically falling rain makes slanted 45° streaks on the side windows of a moving car, the speed of the car

Correct AnswerverifiedShow Answer

When a skateboarder pushes on a wall,

Correct AnswerverifiedShow Answer

Two equal-size vectors at right angles to each other have a resultant that is

Correct AnswerverifiedShow Answer

Harry pulls on the end of a spring attached to a wall. The reaction to Harry's pull on the spring is

Correct AnswerverifiedShow Answer

An archer shoots an arrow. Consider the action force to be the bowstring against the arrow. The reaction to this force is the

Correct AnswerverifiedShow Answer

One end of a rope is pulled with 100 N, while the opposite end also is pulled with 100 N. The tension in the rope is

Correct AnswerverifiedShow Answer

Action and reaction pairs of forces

Correct AnswerverifiedShow Answer

To say there is no such thing as only one force means

Correct AnswerverifiedShow Answer

When Nellie hangs suspended from a pair of ropes that are not vertical, the tension in each rope is

Correct AnswerverifiedShow Answer

When a ball falls downward, it may have a net force

Correct AnswerverifiedShow Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified