What will be the formula used to find work done against resistance if loss in potential energy and gain in kinetic energy is given?

1 Answer
Apr 16, 2018

#W_"dar" = PE_"lost" - KE_"gain"# (notice below what I have chosen those variable names to represent).

Explanation:

Energy is not destroyed. But if one type of energy has decreased, that lost energy must have gone somewhere.

We have to assume work done against resistance, #W_"dar"#, and gain in kinetic energy, #KE_"gain"#, are the only types of energy that could have received that lost potential energy, #PE_"lost"#. Therefore

#PE_"lost" = W_"dar" + KE_"gain"#

If you know #PE_"lost" and KE_"gain"# then

#W_"dar" = PE_"lost" - KE_"gain"#

I hope this helps,
Steve