Question

Q2. a)Calculate work required to be done to stop a car of 1500 kg moving at a velocity of 60km/h. b)A car weighing 1200 kg is uniformly accelerated from rest and covers a distance of 40m in 5s. Calculate the work done by the engine of car during this time. What is the final kinetic energy of car. 

​

Answer 1

Answer:

When a object is moving with a constant velocity, it possess K.E

K.E=

2

1

×m×v

2

So, in order to bring the object to rest i.e its same magnitude of energy is required so, as the final final energy comes to zero.

v=60km/hr=16.66m/s

So, magnitude of work that needs to be done =

2

1

×m×v

2

Hence, work required to stop the car =

2

1

×1500×16.66

2

=208166.7J=208.17kJ