How Much Heat Does a Weightlifter Produce in a Lift?

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To determine the heat produced by a weightlifter lifting a 147 kg weight over 1.1 m, the internal energy change is given as -3620 J. Using the equation delta U = Q - W, where W is the work done (calculated as 9.8 * 147 * 1.1), the heat output Q is found to be -2035.34 J. The discussion clarifies that Q is measured in Joules, and conversion to kilocalories can be done using the factor that 1 kcal is approximately 4184 J. Therefore, the heat output in kilocalories can be calculated from the Joules value. Understanding these conversions is essential for accurate thermodynamic analysis.
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Homework Statement


A weight lifter manages to lift a 147 kg weight a distance of 1.1 m. Treat her as a thermodynamic system and find how much heat (in kcal) she must put out if her internal energy decreases by 3620 J during the lift.


Homework Equations



delta U=Q-W

The Attempt at a Solution



-3620= Q-(9.8*147*1.1)
Q=-2035.34

I was wondering wut the units of Q are? if it's in joules how do i convert to kcal?

Thanks in advance!:smile:
 
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Q is in Joules because you have used consistent metric units.
A kCal is approx 4184J - it's the energy need to heat 1cc of water 1deg C.
 

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