Question

A 24.0-kg dog running at a speed of 3.0 m/s jumps onto a stationary skateboard that has a mass of 3.6 kg. What force with a magnitude of 9.0 N is required to stop the skateboard and dog?

Answer 1

The force required to stop the skateboard and dog is 72.0 N.

Step-by-step explanation:

To find the force required to stop the skateboard and dog, we need to use the concept of conservation of momentum. Before the jump, the dog has momentum given by mass times velocity: 24.0 kg * 3.0 m/s = 72.0 kg*m/s. After the jump, the combined mass of the dog and skateboard is 24.0 kg + 3.6 kg = 27.6 kg. To stop, the momentum must be reduced to zero. Therefore, the change in momentum is 72.0 kg*m/s.

Using Newton's second law, F = Δp/Δt, we can calculate the force required to change the momentum. Assuming it takes 1 second to stop, the force required is given by 72.0 kg*m/s / 1s = 72.0 N.