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

Answer:

Speed of Blythe is 9.8 m/s.

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

$m_{B}v_{B}+m_{G}v_{G}=0$

$v_{B}=-\dfrac{m_{G}v_{G}}{m_{B}}$

Put the value into the formula

$v_{B}=-\dfrac{79\times5}{40}$

$v_{B}=-9.8\ m/s$

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

Hence, Speed of Blythe is 9.8 m/s.

Answer 2

9.9 m/s

calculations below