Physics Question involving vectors and force?

Question

A horizontal force of 805 N is needed to drag a crate across a horizontal floor with a constant speed. You drag the crate using a rope held at an angle of 32 degrees above horizontal. What is the force you exerted on the rope? (I thought the answer was 671.5, but that was not correct)

? · Answer

From the first condition, 805 = µ*m*g → µ = 805/(m*g) = 82.143/m

At 32°, F*cosΘ = µ[m*g - F*sinΘ]
or
F = 805/[cosΘ + 805*sinΘ/mg] = 805/[0.848 + 43.53/m]

So, without knowing m, there is no numerical solution.  If m is large, the answer reduces to Eric's answer.  If small, it becomes less than 805 N

Eric · Answer

805=Fcos(32)
F=805/cos(32)=949.2N

Physics Question involving vectors and force?

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