Power from applied force at 37 degrees to horizontal

  • Thread starter Thread starter nelly42688
  • Start date Start date
  • Tags Tags
    Homework
Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
4 replies · 6K views
nelly42688
Messages
10
Reaction score
0

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[tex]^{}2[/tex] watts but not sure where to go from here thanks
 
Physics news on Phys.org
In this problem mass is not needed.
 
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
 
nelly42688 said:
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) = ?
 
wow! the whole time i was using 5.7m/s instead of 5m/s careless mistake sorry to waste your time