# A force is applied on a car of mass 1500kg ,so that its speed increases from 54km/h to 72km /h .Find the work done by the force on a car .

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by dhanvi

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by dhanvi

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Hi there,

mass=1500kg

initial velocity=54 km/h=15m/s

final velocity=72 km/h=20m/s

initial kinetic energy=1/2m u^2=1/2*1500*225=168750 j

final kinetic energy=1/2*mu^2=1/2*1500*400=300000 j

therefore work =300000-168750=131250 j.

i hope this helps u....

mass=1500kg

initial velocity=54 km/h=15m/s

final velocity=72 km/h=20m/s

initial kinetic energy=1/2m u^2=1/2*1500*225=168750 j

final kinetic energy=1/2*mu^2=1/2*1500*400=300000 j

therefore work =300000-168750=131250 j.

i hope this helps u....

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.

By Work Energy Theorem,

Change in Kinetic Energy=Work done= 1/2 mv² - 1/2 mu²

m=1500 kg

u=54km/h= 54*5/18= 15 m/s

v=72km/h=72*5/18= 20 m/s

W= 1/2 mv²-1/2 mu²

= 1/2*1500*20² - 1/2*1500*15²

= 750*400 - 750*225

=750(400-225)

=750*175

= 131250 J

W = 131.250 KJ

Change in Kinetic Energy=Work done= 1/2 mv² - 1/2 mu²

m=1500 kg

u=54km/h= 54*5/18= 15 m/s

v=72km/h=72*5/18= 20 m/s

W= 1/2 mv²-1/2 mu²

= 1/2*1500*20² - 1/2*1500*15²

= 750*400 - 750*225

=750(400-225)

=750*175

= 131250 J

W = 131.250 KJ