Question

cori uses 475 j of energy from her muscles to push a bar 1 m on a weight machine at the gym. between the bars motion, the heat generated by the machine, and all other types of work done by the machine, j of output work will be done.

Explanation:

Step1: Apply energy - work principle

According to the law of conservation of energy, the energy input is equal to the work output (neglecting any losses in an ideal - like situation where all the muscle energy is converted to work). Here, the energy Cori uses from her muscles is the input energy. The work done by the machine (including all types of work such as the bar's motion, heat generation etc.) is the output work. Since the input energy from her muscles is 475 J, the output work done by the machine is also 475 J.

Answer:

475