5.1.2 Solving Problems Using Linear Momentum and Impulse

Question 1

Solving Problems Using Linear Momentum and Impulse

Answer 1

• Momentum and impulse are defined quantities with physical significance.
• There are situations where you cannot apply Newton’s second law because the forces are difficult to calculate or measure.In these cases, the concept of impulse is particularly useful.
• Impulse can be used to calculate force: .
• Hard collisions are brief and forceful, while soft collisions last longer and are less forceful.
• Remember that impulse and momentum are vector quantities

Question 2

A baseball player hits a 30 m / s pitch back to the pitcher at 35 m / s. Assuming that the baseball has a mass of 0.4 kg, how much impulse did the player give the ball?

Answer 2

26 kg(m / s)

Question 3

A 30 kg concrete block falls 50 m to the ground where it makes contact for 0.1 s. How much force does the block exert on the ground when it lands?

Answer 3

9,391 N

Question 4

A car equipped with airbags and crumple zones is moving at 30 m / s (108 mph) as it crashes into a brick wall. The 80 kg driver collides with the steering wheel for 0.5 s. How much force does the driver experience?

Answer 4

4,800 N

Question 5

A driver weighting 80 kg crashes into a brick wall at a speed of 30 m / s. Which of the following graphs represents the force on a driver in a car with airbags and crumple zones as compared to the force on a driver without airbags and crumple zones?

Answer 5

-

Question 6

A car moving at 30 m / s (108 mph) crashes into a brick wall, and the 80 kg driver comes in contact with the steering wheel for 0.01 s. How much force does the driver experience?

Answer 6

240,000 N

Question 7

A car moving at 30 m / s crashes into a brick wall, and the 80 kg driver comes in contact with the steering wheel for 0.01s. If the driver were wearing a seat belt, how would it affect the situation?

Answer 7

The seat belt would exert the same force on him over a longer period of time.

Question 8

A tennis ball with a mass of 0.5 kg and a velocity of 4 m / s is bounced off a wall at a 60° angle. How much force does it exert on the wall if its contact lasts 0.01 s?

Answer 8

346 N

Question 9

A magician is attempting to yank a tablecloth from a table, leaving the place settings intact. How can he ensure that it works?

Answer 9

Minimize the contact time.