Help with finding Normal Force of inclined plane

AI Thread Summary
To find the acceleration of a 250-kg crate on a 30° inclined plane with a coefficient of kinetic friction of 0.22, it's crucial to correctly calculate the normal force. The applied horizontal force of 5000 N affects the normal force differently than if it were applied parallel to the incline. The normal force should be calculated considering both the weight of the crate and the vertical component of the applied force. A free body diagram is recommended to visualize the forces acting on the crate for accurate calculations. Properly adjusting the normal force will lead to the correct acceleration value.
Bob Johnson
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So this is the problem:
A 250-kg crate is on a rough ramp, inclined at 30° above the horizontal. The coefficient of kinetic friction between the crate and ramp is 0.22. A horizontal force of 5000 N is applied to the crate, pushing it up the ramp. What is the acceleration of the crate?

Relevant Equations: F = ma, F_k=U_kn

I did it, but my answer was 13.23 m/s^2. This was from (5000 - 2450*sin(30) - 0.22(2450)cos(30))/250.

I think I messed up my normal force calculation, which was 250*9.8 cos(30). I looked online, and other people said normal force was equal to Fsin(30) +mgcos(30), which doesn't make sense to me. If possible could someone walk me through finding the normal force?
Thanks!
 
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Your solution would be correct if the 5000 N force is applied parallel to the inclined plane. But, it is actually applied horizontally. Be sure to draw a good free body diagram.
 
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