Question

A 5kg box is pulled for a distance of 12m with a force of 20N along frictionless surface. The force is applied at an angle that is 15 deg. above the horizontal. a.) how much work was done by the applied force? b) how fast will the box be moving at the end of the 12m if it started from rest? c.) if box experiences frictional surfact at end of first 12m and 20N force is no longer acting on object, what must coeff. of kin.friction in order for box to come to rest in exactly 15m.

Answer 1

a) Fcos15 d1
b) W = 1/2mv^2
c) 1/2mv^2 = mu(mg) d2
d1 = 12, d2 =15