A force of 20 ~N is applied on a body of mass 5 ~kg resting on a horizontal plane. The body gains a kinetic energy of 10 ~J after it moves a distance 2 ~m . The frictional force is

Step-by-step solution

Given, force F=20 ~N m=5 ~kg Net force on the body, F_ net =F-f_ s [where, _ s = friction] Work done by displacing 2 ~m is given as aligned W &=F_ net displacement &= (F-f_ s ) 2 &= (20-f_ s ) 2 W &=40-2 f_ s aligned According to work-energy theorem, Work done = gain in kinetic energy aligned & 40-2 f_ s &=10 & 2 f_ s =40-10 &=30 & f_ s &= 30 2 &=15 ~N aligned