# Physics problem in work, power and energy?

A truck weighing 1000 kgf changes its speed from 36 km/hr to 72 km/hr in 2 minutes . Calculate the

(1) work done by the engine

(2) and its power

Take g as 10m/s^2

Please tell me how to solve this problem and show the working as well

:)

Relevance

72 km/h = 20 m/s

36km/h = 10 m /s

Work done by the engine is the change in kinetic energy of the body.

= 0.5 * 1000*( 20^2 – 10^2) = 150000 J

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Power = work /time = 150000/ (2*60) = 125 J/s = 1250 W

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• The mass of 15kg has already been secure contained in the calculation to get 120N. artwork finished = one hundred twenty x 6.2 = 744J Time taken = 6.2 ÷ 3.2 = a million.94s capacity = 744 ÷ a million.ninety 4 = 383.5J/s (Watts)

• These questions are so old I can't remember them anyway:

(1) W=Fxd

F is force

d is distance

F=mxg

F=1000x10

F=10^4

V=m/s m=Vxs (m is distance in meters)

V1 is 36x1000/3600

v2 is 72x1000/3600

V=Vf-Vi

V=V2-V1

M=Vx2x60

W=Fxd

(20) P=W/t

P=W/2x60

I hope i am totally correct :P