Physics prob 2 Help needed

  • #1
Physics prob 2 ... Help needed!!!

Homework Statement



Like i sayed in my other posts this is probably easy but my teacher doesn't teach us anything so i don't have a clue how to do this. Can someone please explain how to do it?

A window washer pushes a sponge up a vertical window at a constant speed by applying a force. The sponge has a mass of .800 kg, and the coefficient of kinetic friction between the sponge and window is u_k=0.253. Determine the magnitude of the applied force, and the magnitude of the normal force exerted by the window on the sponge.

*There is a 20 degree angle( i put the pic below)

Homework Equations



F(y) = weight of sponge + Frictional force

F(f) = u*F(x)

The Attempt at a Solution



ok so what i did was that i took the sin 70 which if i'm not mistaken should equal F(x).
sin 70=F(x)
.94=F(x)

Then I put this in the equation for frictional force.
F(f)=uF(x)
F(f)=(.253)(.94)
F(f)=.238

After that I put it in to the equation for F(y).
F(y)=weight of sponge + F(f)
F(y)=(.8)+(.238)
F(y)=1.048

My plan is to do the pythagorian therum to find the applied force, but I want to make sure i am doing it right so far.
 

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Answers and Replies

  • #2
Redbelly98
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F(x) = F * sin(70)

where F is magnitude of the applied force.
 

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