What is the velocity of the skateboard after Jess falls off?

[bnelson]

Homework Statement

Jess, who weighs 50 kg, is riding a 10 kg skateboard. The skateboard and Jess are moving east at 5 m/s. Jess falls off the skateboard and hits the ground at 4 m/s east, relative to the ground. Calculate the velocity of the skateboard.

Homework Equations

The Attempt at a Solution

 

[cks]

It's the rule of this forum that you have to show your attempt of your question.

BTW, I don't really understand your question, what does it really mean of hits the ground at 4 m/s ?

 

[ogb p]

To calculate the velocity of the skateboard, we can use the conservation of momentum principle. This principle states that the total momentum of a system remains constant unless external forces act on it. In this case, the initial momentum of the system (Jess and the skateboard) is equal to the final momentum after Jess falls off.

Initially, the total momentum is equal to the product of the mass of Jess (50 kg) and the initial velocity of the system (5 m/s). This gives us a total initial momentum of 250 kg*m/s.

After Jess falls off, the final momentum of the system is equal to the product of the mass of the skateboard (10 kg) and its final velocity (unknown). This gives us a final momentum of 40 kg*m/s.

Since the total momentum must remain constant, we can set the initial momentum equal to the final momentum and solve for the final velocity of the skateboard.

250 kg*m/s = 40 kg*m/s * final velocity

Final velocity = 250 kg*m/s / 40 kg = 6.25 m/s

Therefore, the velocity of the skateboard after Jess falls off is 6.25 m/s east, relative to the ground. This calculation assumes that there are no external forces acting on the system, such as friction or air resistance.