5.2 Momentum, impulse and force [Mastery check]

impulsive force is

• the change in velocity

• the rate of change in momentum

• the change in acceleration

• the rate of change in inertia

impulse is

• the change in momentum

• the rate of change in momentum

• the rate of force acting

• the change in inertia

a boy bending his knees when jumping down from a fence. the boy bends his knee so that the impact of the impulsive force on his leg will be

• bigger

• smaller

• the same

which of the following will reduce impulsive force

• increase in velocity

• increase in mass

• increase in time

• increase in acceleration

which of the following causes increase in impulsive force?

• a long jumper landing on a sandy pit

• an airbag acting on a driver during an accident

• a softball player wearing a thick and soft glove to catch a ball

• a boy jumping down with straightened legs.

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

• 66 N·s

• None of these

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

During a collision. an object experiences an impulse. How can this impulse be calculated?

• Multiplying force by time

• Multiplying mass by velocity

• Dividing velocity by time

• Multiplying mass by acceleration

During a collision. an object experiences an impulse. The impulse causes and is equal to the _____ of the object

• energy change

• kinetic energy change

• force

• momentum

• momentum change

What is the function of mattress in a high jump competition?

• To reduce the collision time between the athlete and the mattress

• To reduce the change of momentum of the athlete when he hits the mattress

• To reduce the impulsive force acting on the athlete when he hits the mattress