- #1
Saraballs
- 3
- 0
Homework Statement
A crate is pushed at constant velocity across a rough, horizontal surface by a push force P. The crate has a weight of 73N. Coefficient of kinetic friction between the crate and the floor is 0.41. Vector force P points at an angle of 37 degrees below the horizontal. What is the magnitude of the normal force?
Homework Equations
fk = μkN
constant velocity indicates v0=vfinal and therefore a=0
no movement in the y direction, therefore ƩFy=0
These are random things that I have found online but I'm not sure if they're true:
Fcosθ=f (The horizontal component of the push force is equivalent to to friction)
The Attempt at a Solution
The problem is, I don't have the magnitude of the push force. I don't know where to go from here, but I have tried many things.
To find the kinetic friction:
fk = μkN
=(0.41)(73N)
=29.9N
Using Fcosθ=f, I assume that 29.9N is the horizontal component of the push force. I then find the vertical component of the push force:
Py=29.9N*tan37
Py=19.6N
I then add this to the weight to find the Normal Force:
73+19.6=92.6NThe Normal Force is not 92.6N. This problem is from an exam I failed last semester, and I have the correct answer now, but I can't get to it.
Thank you in advance, for anyone who can help me out.
Last edited: