Let's denote the mass of the boy as M.
According to the conservation of momentum, the total momentum before the boy tosses the jug is equal to the total momentum after he tosses it.
Initial momentum before tossing the jug = 0
Final momentum after tossing the jug = momentum of the boy and skateboard + momentum of the jug
Final momentum = (M + 2.0 kg) * -0.60 m/s + 8.0 kg * 3.0 m/s
Final momentum = -0.60M - 1.20 + 24
Setting the initial momentum equal to the final momentum:
0 = -0.60M + 22.80
0.60M = 22.80
M = 22.80 / 0.60
M = 38 kg
Therefore, the boy's mass is 38 kg.
A boy on a 2.0 kg skateboard initially at rest tosses an 8.0 kg jug of water in the forward direction. If the jug has a speed of 3.0 m/s relative to the ground and the boy and the skateboard move in the opposite direction at 0.60 m/s, find the boy's mass.
1 answer
1 answer