Question

A force acting on a body of mass 20 kg moving with velocity of 40 m/s . the body attains a velocity of 50 m/s in 2 sec .calculate work done by body

Answer 1

Heya!

Mass of a body = 20 kg

Its initial velocity = 40 m/s

Its final velocity = 50 m/s

Time taken = 2 second

Then,

Acceleration (a) =( final velocity - initial velocity) / time

= ( v - u ) / t

= ( 50 - 40 ) / 2

= 10 / 2 = 5 m/s ^2

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Now,

According to third equation of motion,

v^2 - u^2 = 2as

=) (50)^2 - (40)^2 = 2*5*s

=) 2500 - 1600 = 10 s

=) 900 = 10 s

=) s = 90 m

Hence, displacement = 90 m

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Now,

Force = m*a

= 20 * 5

= 100 N

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Now,

Work = force * displacement

= 100 * 90

= 9000 J

Hope it helps u.