Final answer:
The mass of the skateboard is approximately 13.33 kg. To determine the mass of the skateboard, we can use the principle of conservation of momentum. According to this principle, the momentum before the jump is equal to the momentum after the jump.
Step-by-step explanation:
The momentum of the boy before the jump can be calculated by multiplying his mass (40 kg) by his initial velocity (4 m/s), so it is 160 kg·m/s.
The momentum of the boy and the skateboard after the jump is equal to their combined mass
(40 kg + skateboard mass) multiplied by their final velocity (6 m/s). So, we have (40 kg + skateboard mass) * 6 m/s = 160 kg·m/s.
Solving for the skateboard mass, we get:
(40 kg + skateboard mass) * 6 m/s = 160 kg·m/s
240 kg + 6 skateboard mass = 160 kg·m/s
6 skateboard mass = 160 kg·m/s - 240 kg
6 skateboard mass = -80 kg·m/s
skateboard mass = -80 kg·m/s / 6
skateboard mass ≈ -13.33 kg
The negative mass does not make sense in this context, so the mass of the skateboard would be approximately 13.33 kg.