Tennis Ball Collision Homework Solution

[Of Mike and Men]

Homework Statement

A 0.060 kg tennis ball, moving with a speed of 2.50 m/s has a head on collision with a 0.090 kg ball initially moving toward it with a speed of 1.00 m/s. Assuming a perfectly elastic collision, what is the speed and direction of each ball after the collision?

Homework Equations

m₁v₁ + m₂v₂ = m₁v₁' +m₂v₂'

v₁-v₂ = v₂' - v₁'

The Attempt at a Solution

I drew my positive x-direction to the right. Thus, ball 1 is going to the right prior to the collision and ball 2 is going to the left prior to the collision.v₁' = (m₁v₁ + m₂v₂ - m₂v₂') / m1

v₁' = (0.06(2.5)-0.09-0.09v₂')/(0.06)
v₁' = (0.06 - 0.09v₂')/0.06
v₁' = -1.5v₂'

v₁-v₂ = v₂' - v₁'
2.5+1 = 2.5v₂'
v₂' = 1.40
1.40 m/s to the right

v₁' = v₂' - v₁ + v₂
v₁' = 1.4 - 2.5 - 1
v₁' = -2.1
2.10 m/s to the left

Does this look correct?

 

[PeroK]

Does this look correct?

You could check whether momentum is indeed conserved in your solution.

 

[Of Mike and Men]

Duh. Thanks. :)