Physics question

Question

Suppose the two speeds of a two canoes after they are pushed apart are 0.60 m/s for canoe 1 and 0.45 m/s for canoe 2.  if the mass of canoe 1 is 350kg, what is the mass of canoe 2?

Answer 1

Assuming that the canoes were at rest when they were pushed apart, the total momentum in the system must be zero.  This means that the momentum of canoe 1 must have the same magnitude as the momentum of canoe 2, but in opposite directions.

p₁ = -p₂

m₁v₁ = -m₂v₂

m₁v₁/(-v₂) = m₂

m₂ = 350kg(0.60m/s)/[-(-0.45m/s)]

m_x = 470 kg (Rounded to 2 significant figures)