2.4 Review #1

What is linear momentum?

p = m•v

• the product of the mass of a body times its velocity

• the product of the mass of a body times its speed

• the product of the change in mass of a body times its velocity

• the product of the mass of a body times its change in velocity

Choose the INCORRECT unit for momentum.

p = mv and ∆p = F•∆t

• kgms⁻¹

• kgm/s

• Ns

• N/s

Choose the two correct options for the real 2nd Newton's Law defintion.

The average ________ on a system is equal to the rate of _____________ of the system.

• net force, change of momentum

• net force, change of pressure

• net mass, change of momentum

• net mass, change of pressure

Choose the correct option to express that mass in changing according to time.

• F = v•∆m/∆t

• F = ∆v•m/∆t

• F = m•∆a

• F = ∆m•a

A toy car of 2.0 kg of mass was traveling at +3.0 m/s and after 2.0 seconds changed to +6.0 m/s

Choose the INCORRECT option to find its change in momentum:

• (2.0) (6.0 - 3.0)

• m•∆v

• (2.0) (3.0 - 6.0)

• (2.0 • 6.0) - (2.0 • 3.0)

A toy car of 2.0 kg of mass was traveling at +3.0 m/s and after 2.0 seconds changed to +6.0 m/s

Choose the INCORRECT option to find its net force to change the motion:

• [(2.0) (6.0 - 3.0)] / 2.0 s

• m•∆v / ∆t

• [(2.0) (3.0 - 6.0)] / ∆t

• [(2.0 • 6.0) - (2.0 • 3.0)] / ∆t

Find the average force from t=0 to t=4

Hint: ∆p = F_avg * ∆t

• 6.0 N

• 12 N

• 0 N

• 3.0 N

Find the INCORRECT option to find the Impulse (or ∆p) from t=0 to t=4

• 12 N * 4s = 24 Ns

• 1/2 * 4 • 12

• The area under the line

• J = F_avg • ∆t

Choose the INCORRECT description of this graph about a moving object starting from rest.

• Constant force = 6.0 N

• ∆t = 6.0 s

• Impulse = 36 Ns

• ∆p = 36 Ns

• Initial momentum = 6 * 2 = 12 Ns

The graph represents when an object bounces off the floor.

Choose what is the INCORRECT description.

• Line under the curve = Impulse

• Impulse to move object upwards t=2.0 to t=3.0 ms

• ∆t = 2.0 ms

• Impulse to stop object from t=1.0 to t=2.0 ms

• Impulse to stop object 4N • 2.0 ms