Answer:
The correct answer is 5.7
Explanation:
1) Physical principle: conservation of momentum.
If there is not net external force acting on a systmen, then the total momentum of the system is conserved.The momentum, p, is a vectorial magnitude defined as the product of the mass by the velocity: p = mv.
2) In consequence, considering that there is no net force on the system, Sheila and the bike’s momentum before and after the collision is the same.
So, now do the calculations:
Momentum before the collision:
p₁ = (mass of Sheila + mass of the bike)×velocity
p₁ = (60kg + m) × v₁ = 340 kg • m/s
Momentum after collision:
p₂ = mass of sheila × velocity of Sheila + mass of the bike × velocity of the bike
p₂ = 60kg × v₂ + m×0 = 60kg × v₂
p₁ = p₂ ⇒ (60kg + m) × v₁ = 60kg × v₂ ⇒ 340 kg • m/s = 60kg × v₂
⇒ v₂ = 340 kg • m/s / 60 kg ≈ 5.7 m/s ← answer
Final reflection: since the momentum is conserved and the bike stops completely after the collision, Sheila wil keep the total momentum, and you can calculate her velocity dividing the total momentum by her mass: v = 340 kg • m/s / 60 kg ≈ 5.7 m/s
