Question

Michelle and Isabella are ice skating together. Michelle has a mass of 80 kg and Isabella has a mass of 50 kg. Both are at rest and and Isabella pushes of Michelle causing Isabella to move away at a speed of 4.0 m/s. Determine Michelle's speed.

Answer 1

2.5 m/s

Explanation:

Answer 2

2.5 m/s

Step-by-step explanation:

We assume the skates are positioned so that the motion is essentially frictionless.

Conservation of momentum tells you Michelle's velocity (v) must satisfy ...

∑mv = 0

(80 kg)(v) + (50 kg)(4 m/s) = 0

v = -(50 kg)(4 m/s)/(80 kg) = -2.5 m/s

Michelle's speed is 2.5 m/s in the direction opposite Isabella's.