Question

A car of mass 1000 kg accelerates uniformly from rest to a velocity of 54 km/hr in 5 sec. Calculate
(a) its acceleration
(b) its gain in KE
(c) average power of the engine during this period

Answer 1

a)    a = (v2-v1)/t

Convert 54km/h into m/s which is 15m/s

a = (15-0)/5

a = 3m/s^2

The acceleration is 3 m/s^2.

b)    KE = 1/2mv^2

KE = 1/2 (1000) (15)^2

KE = 112500 J

The car gains 112,500 J. It started from rest so we know that the initial KE was 0.

c) P = work/time

P = 112500/5

P = 22500 W

The average power of the engine is 22,500 watts (W).

Answer 2

hope this will clear your doubt
all the best for the exams