Question

Calculate the work required to be done to stop a car of 1500kg moving at a velocity of 60 km/hr?

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.

So, magnitude of work that needs to be done =

2

1

×m×v

2

60km/hr=16.66m/s

So, work required to stop the car =

2

1

×1500×16.66

2

⇒=208166.7J=208.17kJ

Explanation:

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Answer 2

Heya!!!

Here is your answer -

Mass of the car m = 1500 kg  

Velocity of the car v = 60 km/h  

= 60×1000 /60×60 = 50 /3 m/s

The car is in motion, so its energy = kinetic energy = 1 /2 mv2

= 1 /2 (1500) ( 50/ 3 ) 2 J  

= 1/ 2 × (1500) × 2500/ 9 J  

= 208333.3 J

The kinetic energy of the car, when it comes to rest = 0 J  

Work done on object = change in kinetic energy  

= 208333.3 − 0 J  

= 208333.3 J  

Hence, the work required to stop the car is 208333.3 J