Check Your Answers Collision Review

Impulse will cause a _______ in an object’s momentum.

• change

• increase

• decrease

• constant

A mass of 45 kg is traveling right at 5.0 m/s. What is the momentum?

• 225 kg·m/s

• 45 kg·m/s

• 5.0 kg·m/s

• 2250 kg·m/s

Answer explanation

Momentum is mass x velocity

A 10 kg object traveling right at 4 m/s hits a 5 kg stationary object and sticks to it. Find the original net momentum and the velocity of the two objects as they roll away.

• 40 kg m/s, 2.67 m/s

• 40 kg m/s, 4 m/s

• 35 kg m/s, 2.67 m/s

• 40 kg m/s, 4.5 m/s

Answer explanation

Net momentum = (mass x velocity) + (Mass x velocity) Stationary objects have a velocity = 0

A 30 kg object traveling right at 5 m/s hits a 20 kg object traveling right at 1 m/s and sticks together. What is the net momentum and the velocity of the two objects as they roll away as one?

• Net momentum: 170 kg m/s, Velocity: 3.4 m/s

• Net momentum: 150 kg m/s, Velocity: 3.0 m/s

• Net momentum: 190 kg m/s, Velocity: 3.8 m/s

• Net momentum: 200 kg m/s, Velocity: 4.0 m/s

A 10 kg object traveling right at 4 m/s hits a 40 kg object traveling left at 3 m/s when stuck together. Find the net momentum and the velocity of the two as they roll away.

• Net momentum = 80 kg·m/s, final velocity = 1.6 m/s

• Net momentum = -80 kg·m/s, final velocity = -1.6 m/s

• Net momentum = 80 kg·m/s, final velocity = -1.6 m/s

• Net momentum = -80 kg·m/s, final velocity = 1.6 m/s

Answer explanation

Net momentum = (mass x velocity) + (mass x velocity) If they are going in opposite directions, one of the velocities will be NEGATIVE. Left is considered a negative velocity.

A 30 kg object: a. is moving at 10 m/s right. Find the momentum _______.

• The momentum of the object can be calculated using the formula: momentum = mass × velocity. Here, mass = 30 kg and velocity = 10 m/s. Therefore, momentum = 30 kg × 10 m/s = 300 kg·m/s.

• The momentum of the object is calculated by multiplying mass by the square of velocity, giving 30 kg × 100 m²/s² = 3000 kg·m/s.

• The momentum of the object is given by mass divided by velocity, which is 30 kg / 10 m/s = 3 kg·m/s.

• The momentum of the object is zero when it's at 10 m/s since momentum only applies to stationary objects.

A 30 kg object: b. is moving at 30 m/s right. Find the momentum _______.

• 0

• 900

• 30

• 90

Calculate the change in momentum to a 20 kg object that experiences a force of 50 N for 2.5 seconds to the right.

• 125 Ns to the right

• 250 Ns to the right

• 75 Ns to the right

• 50 Ns to the right

Answer explanation

CHANGE in momentum is the same equation as impulse = force x time.

Explain the difference between the astronaut's mass and weight on each planet. How does it affect momentum?

• Mass remains constant while weight varies due to different gravitational forces. Since momentum is mass x velocity, momentum would not change on different planets.

• Both mass and weight vary based on gravitational forces. Since momentum is mass x velocity, momentum would change be different on different planets.

• Mass varies while weight is determined by the astronaut's composition. Weight would be the same on the different planets just like momentum.

• Neither mass nor weight change regardless of the planet. Since weight changes, so would momentum.

A 35 kg object is moving at 3.5 m/s to the right and a force of 150 N is applied for 2.7 seconds. What is the object’s original momentum?

• 122.5 kg·m/s

• 150 kg·m/s

• 135 kg·m/s

• 105 kg·m/s

Answer explanation

Mass x velocity =