1)    A boy with a mass of 48 kg runs down an incline with a skateboard with an initial velocity of 
16 m/s. What would be the final velocity (at the foot of the incline) of the boy and the work done by him (from top to the foot of the incline)?   

2)    A skater with a mass of 70 kg wants to move up a mountain with an initial velocity of 23 m/s. What would be the final velocity (at the top of the mountain) of the skater and the work done by him (from foot to the top)?