Question

certain force acting on a 20 kg mass changes its velocity from
10m/s to 6m/s. calculate the work done by the force​

Answer 1

Answer:

Kinetic energy is given by the expression, (KE)v = 1/2 mv2

Where, KE = Kinetic energy of the object moving with a velocity, v

 Kinetic energy when the object was moving with a velocity of 5 m/s

(KE)5 = 1/2 — 20 — (5)2 = 250 J

Kinetic energy when the object was moving with a velocity 2 m/s

(KE)2 = (1 )/2 x 20 — (2)2 = 40 J.

Work done = Change in kinetic energy

= 40J -250J

= – 210J

Therefore, work done = -210J