Question

the graph between there is resistive force F acting on a body and the distance covered by the body is shown in figure the mass of body is 25 kilogram and initial velocity is 2 m per second when the distance covered by the body is 5 M find its kinetic energy

Answer 1

initial kinetic energy= 1/2 m v ^2
Ki= 1/2 × 25 × 4= 50.
negative work done(w) = area of graph= -40.
Ki + w = Kf( work energy theorem)
=>Kf= 10J.

Answer 2

As we have learnt in, kinetic energy (k) = 1/2 mv2 (Note: m -> mass and v -> velocity). Remember that kinetic energy never comes in negative.

As per the question, m = 25 and velocity = 2.

Put these values in kinetic energy k = 1/2 x 25 x (3)2 => 1/2 x 25 x 9 => 50J.

Work done against resistance force = area between F-x graph => 1/2 x 4 x 20 = 40J. Final kinetic energy = 50J – 40J = 10J.