# A car of mass 1000 kg rests on a horizontal road initially . It is then pushed over 5 m to a speed of 1 m/s before the engine is started . If the average frictional force acting on the car is 500 N,the total work done in moving the car before the driver starts the engine is.

1
by arriyajanyalk

2015-11-08T13:08:07+05:30

### This Is a Certified Answer

Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
Case 1:  The car is pushed from rest to a speed of 1m/s  over a distance of 5 m.
So the car is accelerated during this push.

KE of the car gained due to pushing = 1/2 m v² = 1/2 * 1000 kg * 1² (m/s)²
= 500 J
Work done against friction = friction force * displacement
= 500 N * 5 m = 2,500 J

Total work done in moving the car from rest to a speed of 1 m/s
= 2,500 + 500 = 3, 000 J

=============
Case 2.  The car is pushed at a uniform speed of 1 m/s  over 5 m

Work done in moving the car is against the friction force.
W = F s = 500 N * 5 m = 2,500 J

Since the car is pushed at a uniform speed, the force exerted is equal to the friction force.

click on thanks button above;; select best answer
?? Y my answer was wrong
sir pls explain