A youngster shoots a bottle cap up a 21.5° inclined board at 1.82 m/s. The cap slides in a straight line, slow

Question

A youngster shoots a bottle cap up a 21.5° inclined board at 1.82 m/s. The cap slides in a straight line, slowing to 0.92 m/s after traveling some distance. If the coefficient of kinetic friction is 0.40, find that distance.

Answer 1

Work done by friction force equal to the change in kinetic energy
Wf=Ke1-Ke2
umgcos(21.5) d= 0.5m(V1^2 - V2^2)
d= 0.5m(V1^2 - V2^2)/umgcos(21.5)
d= ((V1^2 - V2^2)/ugcos(21.5)
d= (1.82 ^2 - 0.92^2)/ [2 x 0.4 0 x cos(21.5)]
d= 3.3m