Answer:
The velocity of Billy is, V = - 2.05 m/s
Explanation:
Given data,
The mass of Sally, m = 45 kg
The mass of Billy, M = 55 kg
Sally's velocity, v = 2.5 m/s
Billy's velocity, V = ?
According to the law of conservation of momentum,
mv + MV = 0
V = - (mv/M)
V = - (45 x 2.5 / 55)
= - 2.05 m/s
Hence, the velocity of Billy is, V = - 2.05 m/s