When only the force of gravity dose work on a system, the total mechanical energy of that system is conserved : true or false ?

answer: 802.3 kilo joules of energy represents 191.75 kilo calorie of energy.

explanation:

energy released during combustion of one mole methane = 802.3 kilo joules

if 1 kilo joule = 0.239006   kilo calorie

then ,802.3 kilo joule will be = 802.30.239006 kilo calorie

802.3 kilo joule = 191.75 kilo calorie

hence, the energy in kilo calorie is 191.75 kilo calorie.

we need to know the time interval during which the force acts. impulse of force = momentum change

c) power lifting, will be your answer.

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deku ❤