Question

the work done required to stop a car of mass 1000kg moving at a velocity of 20m/s will be?

Answer 1

Hola User___________________

Here is Your Answer.....!!!!!
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〽Actually welcome to the concept of the WORK ENERGY THEOREM. ..

〽Basically we know that ....

〽Work done = Change in the Kinetic Energy. ....

〽there fore here we know that ... u = 20 m/s and v = 0 m/s ....

〽So applying the theorem we get ....

〽W = 1/2 mv^2 - 1/2mu^2

〽W = 1/2 (1000)(0)^2 - 1/2 (1000)(20)^2

〽W = 0 - (500) × (400)

〽W = - 200000 joules ....

〽There we get that ...

〽Work done = - 200 KJ ....

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⭐Hope it helps u.....☺

Answer 2

Hello friend

work done =change in total energy

here no change in potential energy so we only find change in kinetic energy

First ,to stope the car we need to do zero kinetic energy .

intial kinetic energy of any CAR is given by

K.E.=1/2(M)V^2   [where V=velocity of particle M=mass of particle]

so, K.E.=0.5*1000*20*20=200,000Joule

similarly final K.E=0 [BECAUSE CAR VELOCITY =0]

FROM DEFINITION OF WORKDONE

W=0-200,000=200,000JOULE OR 200KJ

HOPE IT HELPS U