Solving Friction: Finding the Horizontal Force

[homevolend]

Homework Statement

A boy puls a 50 kilogram crate across a level a level floor with a force of 200N. If the force acts at an angle of 30degrees up from the horizontel, and the coefficient of kinetic friction is 0.30. find the horizontal frictional force exerted on the crate by the floor.

Homework Equations

Ff=Fnet-Fa

The Attempt at a Solution

I have tried many things to find the friction. First I found the fnet by doing

fg=mg
fg=50(9.81)
fg=490N

0=FN+Fasin(-)-Fg
0=FN+200sin30-490
0=Fn+100-490
-100=-490FN
FN=390N

Now we have the Fnet I tried to do the Fn-Fa for the friction but it didn't work. 390-200 gives 190 but then I did the rest of the equation and it doesn't work properly.

How do I find friction.

 

[tatiana]

you first need to draw a free body diagram relevant to teh horzontal before you can slove anything!.. the Fnet is just the sum of all the forces acting into opposite direction so you just need to add your forces