Question

A car of mass 500 kg increases its speed from 72 km/h to 108 km/h. Find the increase in its kinetic energy?​

Answer 1

Explanation:

we know kinetic energy, E= (½)mv²

Given, m= 500kg

v'= 72km/h

v"= 108km/h

to find increase in kinetic energy.

now, increase in kinetic energy= E"- E'

increase in kinetic energy= (½)mv"²-(½)mv'²

= (½)m(v"²-v'²)

= (½)500(108²-72²)

= (½)500(108-72)(108+72)

= (½)500(36)(180)

=500(18)(180)

=1620000 × (10³)²/3600²

=1620000×10⁶/12960000

=162×10⁶/1296

=0.125×10⁶

increase in kinetic energy =1.25×10⁵ J.

this is the required answer.