Forces that Change Motion Quick Check
Which of the following best describes the sum of all forces acting on an object?(1 point)
Responses

net force, which is a vector sum
net force, which is a vector sum

gravitational force, which is a vector sum
gravitational force, which is a vector sum

net force, which is a scalar sum
net force, which is a scalar sum

acceleration, which is a vector sum

Suppose a man is sitting on a chair and exerting 100 N of force downward, while a spring beneath the chair exerts 150 N of force upward. If you assign a negative value to the downward force, what is the net force of this system?(1 point)
Responses

250 N
250 N

50 kg
50 kg

-50 N
-50 N

50 N

During a game of pool, a cue ball travels to the left with 70 N of force and collides with the four ball moving with a force of 50 N to the right. If you assign a negative value to the force moving to the right, what is the net force of this system?(1 point)
Responses

-20 N
-20 N

120 N
120 N

20 m/s2
20 m/s2

20 N
20 N
Recall that the formula for momentum is:

P=mv
Which of the following correctly shows momentum being calculated?

(1 point)
Responses

14 kg*/s=(9 kg) (5 m/s)s14 kg * / s = ( 9 kg ) ( 5 m / s ) s

45 kg*m/s=(9 kg) (5 m/s)45 kg * m / s = ( 9 kg ) ( 5 m / s )

4 kg*m/s=(9 kg) (5 m/s)4 kg * m / s = ( 9 kg ) ( 5 m / s )

45 N=(9 kg) (5 m/s)45 N = ( 9 kg ) ( 5 m / s )

A hockey puck with a mass of 0.12 kg is traveling across the ice at a velocity of 150 m/s downfield. What is the momentum of the hockey puck?(1 point)
Responses

P=8*10−4 kg*m/sP = 8 * 10 - 4 kg * m / s

M=18 kg*m/sM = 18 kg * m / s

P=18 NP = 18 N

P=18 kg*m/sP = 18 kg * m / s