Momentum and Impulse

Momentum and Impulse

Momentum

-it is the product of the mass and velocity of an object.

-it is a vector quantity - (it has a magnitude and direction).

Momentum

-All objects have mass. So, if an object is moving, then it has momentum.

Momentum

-when we say momentum, mass is in motion.

Multiple Choice

Which takes more force to catch, a bowling ball or a ping pong ball?

• bowling ball because it has more momentum

• ping pong ball because it has more momentum

• both require the same amount of force when catching

• bowling ball because it has less momentum

Multiple Choice

When the speed of an object is doubled, its momentum

• remains unchanged in accord with the conservation of momentum.

• doubles

• quadruples

• decreases

Momentum

P= mv

wherein,

P= momentum; kg.m/s

m= mass; kg

v= velocity; m/s

Multiple Choice

A 50 kg ball rolls down the street at 5 m/s. Calculate the momentum of the ball.

• 55 kg*m/s

• 100 kg*m/s

• 250 kg*m/s

• 500 kg*m/s

Multiple Choice

A runner has a momentum of 670 kg m/s and is traveling at a velocity of 9 m/s. What is his mass?

• 6030 kg

• 0.0134 kg

• 74.44 kg

• 80 kg

Multiple Choice

A biker with a mass of 75 kg moves along the path with a constant velocity of 5 m/s. What is the biker's momentum?

• 25 m/s

• 375 m/s

• 25 kg m/s

• 375 kg m/s

Multiple Choice

An object with a mass of 2000 kg at rest has what momentum?

• 2000 kg m/sec

• 0 kg m/sec

• 2000 kg

• 2000 m/sec

Multiple Choice

A 10kg toy truck moves at 5m/s East. It collides head-on with a 5kg toy car moving 10 m/s moving west. What is the total momentum of the system?

• 0 kgm/s
• 30 kgm/s
• 50 kgm/s
• 10 kgm/s

How hard is it to stop a moving object?

To stop an object, we have to apply a force over a period of time.

This is called IMPULSE.

I= ΔP wherein I= Impulse Δ= change

Equation: I=ΔP= FΔt

Unit: N.s

Multiple Choice

The impulse-momentum theorem states that

• the impulse on an object is equal to the change in momentum it causes

• the force on a moving object is equal to the magnitude of the impulse.

• the impulse on an object is greater than the change in momentum it causes

• the impulse on an object is less than the change in momentum it causes

Multiple Choice

Cart A is pulled with a 2 Newton force for 2 seconds, and Cart B is pulled with a 1 Newton force for 3 seconds. Which cart experiences the greatest impulse?

• Cart B

• Cart A

• they are the same

Multiple Select

The units for Impulse are

• kg

• $$N\cdot s$$

• N

• m/s

• $$kg\cdot\frac{m}{s}$$

Multiple Choice

A boy kicks a football with a force of 20 N, the time the force acts for is 0.3 s. Calculate the impulse on the ball.

• 1 N⋅s

• 6 N⋅s

• 33.3 N⋅s

Multiple Choice

The velocity of a 975-kg car is changed from 12.0 m/s to 27.0 m/s in 15s by an external, constant force. What is the magnitude of the force?

• 9.75×10² N

• 1.46×10⁴ N

• 9.75×10³ N

• 975 N

Multiple Choice

A constant force of 4.5 N acts on a 7.2-kg object for 10.0 s. What is the change in the object's velocity?

• 6.25 m/s

• 3.23 m/s

• 1.22 m/s

• 4.33 m/s

Multiple Choice

A 5 N force is applied to a 3 kg ball to change its velocity from +9 m/s to +3 m/s. The time for the collision is _____ seconds.

• 1.8

• 2.5

• 3.6

• 10

Multiple Choice

A 5 N force is applied to a 3 kg ball to change its velocity from +9 m/s to +3 m/s. The impulse on the ball is ______ N s.

• -2.5

• -10

• -18

• -45

Multiple Choice

A 40-kilogram mass is moving across a horizontal surface at 5.0 m/s.  What is the magnitude of the net force required to bring the mass to a stop in 8.0 seconds?

• 1 N
• 40 N
• 25 N
• 5 N

Multiple Choice

If an air bag changes a 60 kg person's speed from 40.0 m/s to     0.0 m/s, what impulse must act on the person? 

•  2400 kg.m/s
• 1.5 kg.m/s
• 0.67 kg.m/s
• 1500 kg.m/s