A crate of mass 80kg sits on the floor. the crate must be
brought to the top of a loading dock by sliding it up a ramp 2.5m
long, inclined at 30 degrees. the worker, giving no thought to the
force of friction, calculates that he can get the crate up the ramp
by giving it an initial speed of 5m/s at the bottom and letting it
go. unfortunately, friction is negligible, the crate slides up 1.6m
on the ramp, stops, and slides back down.
using conservation of energy, show that the initial speed of 5.om/s
as calculated by the worker is correct if friction is
negligible
