snow can be extremely taxing because the arms have such a low efficiency in this activity. Suppose a person shoveling a footpath metabolizes food at the rate of 800 W. (a) What is her useful power output? (b) How long will it take her to lift 3000 kg of snow 1.20 m? (This could be the amount of heavy snow on 20 m of footpath.) (c) How much waste heat transfer in kilojoules will she generate in the process?

Step-by-step solution Step 1 of 7 The formula to find the efficiency is, Here is the efficiency, is the output power and is the input power. Step 2 of 7 (a) Use the above formula to find the power output, Step 3 of 7 Substitute for and for . Therefore, the power output is . Step 4 of 7 (b) Use the above formula to find the time, Here is the height, is the mass of the snow.