Question

7. A 77 kg girl and a 62 kg boy face each other on friction free roller skates. The girl pushes the boy, who moves away at a speed of 2.5 m/s. What is the girl's speed? ​

Answer 1

`\sf\longmapsto \: 2.0m/s`

Step-by-step explanation:

Initial momentum = 0

`\sf\longmapsto \: 77 \: velocity + 62 * 2.5 = 0`

`\sf\longmapsto \: 77 \: velocity = - 155`

`\sf\longmapsto \: velocity = ( - 155)/(77)`

`\sf\longmapsto \: \: velocity = - 2.012`

`\sf\longmapsto \: 2.0 \: m/ s`