Question

The 50-kg boy jumps on the 5-kg skateboard with a horizontal velocity of 5 m/s. Determine the distance s the boy reaches up the inclined plane before momentarily coming to rest. Neglect the skateboard's rolling resistance.

Answer 1

the question is incomplete! the angle should be given! And by using conservation of energy the K.E is 687.5 J is converted!

Answer 2

Answer:

Taking the case of the boy

Mass of boy (M1)= 60kg

Initial velocity (u1) = 5m/s

Final velocity (v1)= ?? (To find)

Taking the case of skateboard

Mass of skateboard (m2) =4 kg

Initial velocity (u2) = 0 m/s. (the board is stationary)

Final velocity (v2)= ?? (To find)

Now v1 = v2 ( both are moving in the same direction and the boy is standing on the skate board so velocity will be same)

Using law of conservation of momentum

(mu)1+(mu)2=(mv)1 + (mv)2

(60*5)+(4*0)= v(M1+m2). V1 = V2 proved above

300+0=v(60+4)

300=64v

300÷64= v

V=4.68 m/s