Calculating Power Using Applied Force and Velocity: Quick Homework Question

[nelly42688]

Homework Statement

A 100kg block is pulled at a constant speed of 5.0 m/s across a horizontal floor by an applied force off 122N directed 37 degrees above the horizontal. What is the rate at which the force does work on the block?

Homework Equations

I know here we will use the instantaneous power formula P=dW/dt or P=Fvcos

The Attempt at a Solution

well i drew the FBD and started plugging in numbers in my formula, its just I am not sure where the Mass falls into place here I know the answer is 4.9x10$$^{}2$$ watts but not sure where to go from here thanks

 

[rl.bhat]

In this problem mass is not needed.

 

[nelly42688]

well my answer just doesn't match up with the answer my teacher gave us and i don't know why... i did 122*5.7sin(37) and came up with 418.5W or 4.2X10^2 W

 

[rl.bhat]

well my answer just doesn't match up with the answer my teacher gave us and i don't know why... i did 122*5.7sin(37) and came up with 418.5W or 4.2X10^2 W

Your calculation is wrong.
122*5*cos(37) = ?

 

[nelly42688]

wow! the whole time i was using 5.7m/s instead of 5m/s careless mistake sorry to waste your time