The work done by a boy pulling a snow sled up a hill is 425 J. What is the power expended by the boy if he pulls on the sled for 10.5 s?

1 Answer
Dec 8, 2017

#40.5 " watts"#


Power is simply work done over time. The formal, calculus based definition is:

#P = (dW)/dt#

However, in more simple applications, you can just write this as:

#P = W/t#

You're given work, and you're given time, so we just plug in & solve:

#(425" J")/(10.5" s") = 40.5" watts"#

Note that 1 watt = 1 Joule per second.

Hope that helped :)