another force question?

1. The problem statement, all variables and given/known data
A person has a choice while trying to move a crate across a horizontal pad of concrete: push it at a downward angle of 30 degrees, or pull it at an upward angle of 30 degrees.

If the crate has a mass of 50.0 kg and the coefficient of friction between it and the concrete is 0.750, calculate the force required to move it across the concrete at a constant speed in both situations.

2. The attempt at a solution
I don’t know how to start calculating it by I do have an idea of what the answer will be. In the end, pulling at an upward angle will have a lower force because pulling upward will decrease friction resulting in decrease of normal force.

As for the calculation part, I was thinking of using Fpcos(30°)p = [itex]\mu[/itex]N with N being (mg + Fpsin(30°)) for pushing and then Fpcos(30°) = [itex]\mu[/itex]N with N being (mg – Fpsin(30°)) for pulling but I feel like it’s a bit disorganized since it doesn’t follow what we usually have in class like a parent formula on top and you can manipulate it to get this and that, etc.

http://ift.tt/1jzHMO5

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