9.2 Impact forces

Question 1

What is the equation to calculate the impact force?

Answer 1

» Change of momentum/ time

Question 2

What is the initial momentum of a ball which is heading towards a wall?

Note: it is travelling in the positive direction

Answer 2

» mu
» Where m is the mass and u is the initial velocity

Question 3

What is the momentum when it bounces off the wall?

Note: It is travelling in the negative direciton

Answer 3

» -mv
» Where m is the mass and v is the final velocity

Question 4

What is the change in momentum if there is no loss of speed on the impact?

Use v = u

Answer 4

» -2mu

Question 5

What is an oblique impact?

Answer 5

» The initial direction of the ball is not perpendicular to the wall
» It is coming at an angle to the wall

Question 6

What is the change in momentum of the ball in the normal component direction to the wall?

Answer 6

» -2mucostheta

Question 7

What is the equation to find the change in momentum?

Answer 7

» mv - mu