Answer:
Before: 0 m/s
After: -4 m/s
Explanation:
Before: Since you and your beau started at rest, your beau initial velocity is 0 m/s.
After: Since we have to conserve momentum,
momentum before push = momentum after push.
The momentum before push = 0 (since you and your beau are at rest)
momentum after push = m₁v₁ + m₂v₂ were m₁ = your mass = 60 kg, v₁ = your velocity after push = 3 m/s, m₂ = beau's mass = 45 kg and v₂ = beau's velocity.
So, m₁v₁ + m₂v₂ = 0
m₁v₁ = -m₂v₂
v₂ = -m₁v₁/m₂ = -60 kg × 3 m/s ÷ 45 kg = -4 m/s
So beau moves with a velocity of 4 m/s in the opposite direction
