Question

A block of mass 3 kg slides down a frictionless inclined plane of length 6 m and height 4 m. If the block is released from rest at the top of the incline, what is its speed at the bottom?

Answer 1

(if it's frictionless the length doesn't even matter :) )
It would have the same kinetic energy down as the potential energy up. That is,
`mgh=(mv^2)/(2)` or
`2gh=v^2` (the mass doesn't even matter). The result is
`√(2gh)`, so only the height matters really. It is almost 9 (it is
`√(80)=4√(5)`).