# Express the kinetic energy in KJ when a bike of 80 kg moving with a velocity of 72km h-1

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by dhanvi

2015-11-21T21:32:28+05:30

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Kinetic Energy K=1/2 * m * v²

m=80 kg
v= 72 km/h= 20 m/s

K=1/2 * m * v²
∴K=1/2 * 80* 20²
= 40*400
= 16000 J

1 KJ= 1000 J
So 16000 J= 16 KJ
2015-11-21T22:14:18+05:30

### This Is a Certified Answer

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.
⇒ m = 80 kg

⇒ v = 72 × 5/18 = 20 m/s

⇒ Ek = 1/2 mv²

⇒ Ek = 1/2 × 80 × 20 × 20

⇒ Ek = 32000/2 = 16000J

⇒ Ek = 16kJ