Question

. The power required by engine of car of mass
1000 kg to accelerate it from rest to a speed of
72 km/h in 20 s is

(1) 10 kW
(2) 1 kW
(3) 100 kW
(4) 1000 kW​

Answer 1

Answer:

v = u + at

72km/h = 0 + a(20)

72×5/18 = 20a

we know 1km/h = 5/18 metre per second

a = 1 metre per sec square

force = m × a

force = 1000kg× 1m/s^2

force = 1000 KN

we know that, power = workdone/ time.....(1)

workdone = force× displacement........(2)

displacement = ut+ 1/2 at^2

= o + 1/2 × 1 × (20)(20)

displacement = 200 m put this in (1)

work done = 1000KN × 200m

workdone = 2× 10^5 J

put this in 1

power = 2× 10^5/20

power = 200000/20

power = 100kW

Answer 2

The power required by engine of car of mass 1000 kg to accelerate it from rest to a speed of. 72 km/h in 20 s is. (1) 10 kW.

Your answer is in the image

Thankyou and have a nice day