Question

Blythe and Geoff are ice-skating together. Blythe has a mass of 40 kg and Geoff has a mass of 79 kg. Blythe pushes Geoff in the chest when both are at rest, causing him to move away at a speed of 5 m/s.

Answer 1

9.9 m/s

calculations below

Answer 2

Speed of Blythe is 9.8 m/s.

Step-by-step explanation:

Mass of Blythe =40 kg

Mass of Geoff = 79 kg

Speed = 5 m/s

Suppose, we determine the Blythe's speed after she pushes Geoff

Since, initial momentum is zero final momentum should be zero.

Using momentum of conservation

`m_(B)v_(B)+m_(G)v_(G)=0`

`v_(B)=-(m_(G)v_(G))/(m_(B))`

Put the value into the formula

`v_(B)=-(79*5)/(40)`

`v_(B)=-9.8\ m/s`

Negative sign shows that he move in direction opposite to Geoff.

Hence, Speed of Blythe is 9.8 m/s.