A child of m1=48 kg, is initially standing at rest on a skateboard. The child jumps off the skateboard moving horizontally with a speed v1=1.2 ms^-1. The skateboard moves with a speed v2=16 ms^-1 in the opposite direction. Find the mass of the skateboard.
We approach this problem using the conservation of linear momentum, which tells us that m1 x v1 = m2 x v2. We substitute the values of m1, v1 and v2, and solve for m2: 48x1.2=m2x16; m2=57.6/16=3.6 kg.
