Question

What work is said to be done to increase the velocity of a car 15km/h to 30km/h, if the mass of the car is 1000kg?

Answer 1

m = 1000 kg 

u = 15 km/h = 50/12 m/s

v = 30 km/h = 100/12 m/s

Work done = change in K.E.

K.E. = 1/2 mv² = 1/2 * 1000 * 50/12 * 50/12 = 8680.5 J

K.E. = 1/2 mv² = 1/2 * 1000 * 100/12 * 100/12 = 34722.2 J

34722.2 - 8680.5 = 26041.7 J

Hope it helps you!