Satarting from rest and a height of 10 m, a 2-kg mass slidesdown a 30 degree incline, reaching the bottom with a speed of 10m/s.What is the approximate work done by friction? [a]0 [b]-103 [c]-100J [d]-200J [e]cannot be determined without the coefficient offriction Satarting from rest and a height of 10 m, a 2-kg mass slidesdown a 30 degree incline, reaching the bottom with a speed of 10m/s.What is the approximate work done by friction? [a]0 [b]-103 [c]-100J [d]-200J [e]cannot be determined without the coefficient offriction
Explanation / Answer
The approximate work done by friction is Wf = mgd sin30 -(1/2)mv2 Here m = 2kg g=9.8 m/s2 d = (10m)/sin30 v= 10 m/s On substitution we get Wf = 100 J d = (10m)/sin30 v= 10 m/s On substitution we get Wf = 100 J