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Hey guys, I'm stuck on this question. Don't you need MASS of the object to get F(g)=mg?.. Could be wrong. Help please.

"Pushing a grocery cart with a force of 95N, applied at an angle of 35º down from the horizontal, makes the cart travel at a constant speed of 1.2 m/s. What is the Frictional force acting on the cart?"

So far I got:
F=ma; there are three forces acting on the cart; Ff=F(friction), Fa=F(applied) and Fg=F(gravity)
constant velocity so a=0

Ff+Fa+Fg=ma
Ff=ma-Fa-Fg
Ff=-Fa-Fg
Ff=-95N-(-mgSIN(35º))

Am I on the right track? Don't I need mass?

Thanks in advance.

Last edited by ruben7 (2010-03-05 21:28:57)