Finding F required pushing a box at angle (theta) for constant v

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SUMMARY

The discussion focuses on determining the force F required to keep a crate moving at a constant velocity while being pushed at an angle theta. The key equations involved are the frictional force equation Ff = Uk * Fn and the condition for constant velocity, which states that the net force Fnet must equal zero. The user initially misapplied the trigonometric components of the force, confusing sine and cosine. The correct relationship is established as Uk(mg + Fcos(theta)) = Fsin(theta), leading to the formula F = Uk(mg + Fcos(theta))/sin(theta).

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Homework Statement



a crate with mass m rests on a horizontal floor. a woman pushes down at an angle of theta below the horizontalon the frace with a force F, the coefficient of kinetic friction is Uk.
a) what magnitude of force F is required to keep the crate moving at a constant velocity?

Homework Equations



Ff(frictional force)=UkFn

Constant velocity which means Fnet=0

The Attempt at a Solution



since Fnet is 0 you can set horizontal force = to frictional force

Ff=Fsin(theta)
Uk(mg + Fcos(theta))=Fsin(theta)
(Uk(mg+ Fcos(theta))/sin theta = F

This is apparently not right and i can't thing of what else to do -_- help would be very much appreciated as well as an easier way of approaching problems with only symbols.
thanks!
 
Last edited:
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You are very close, but I think you mixed up the components of F. I think your cos and sin should be switched.
 

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