Help with a physics problem?
You lean a 10 [kg] ladder against a frictionless wall. If the ladder is making a 60 degree angle with the floor, what is the coefficient of static friction between the ladder and the floor so that the ladder does not slide? What assumptions are you making?
October 15, 2015
6 Comments • Newest first
just consider the ladder's motion first... which is the y-component. So friction's force is going to act opposite to that... b/c that's what friction is, opposite/opposing motion. The ladder is going down, so friction is going up. Frictional Force = Fn (Normal force, mg(cos[theta]) because you want it to stop motion/rest.
Frictional Force = Coefficient of Static Friction * Fn = mgCos(theta).... solve for your coefficient.
Yea what xxmcheifxx said, start using them sin and cos
@steffy: That's cause this is AP Physics xD
"What assumptions are you making?"
lol. "i'm assuming the ladder is magnetic and the wall is a very strong electromagnet (strong enough to hold the ladder in place), therefore the coefficient of static friction between the ladder and floor is irrelevant. QED"
in all seriousness, find the normal force and compute the component (this is where the angle comes in) that is in the opposite direction of the friction force, you know the two must be equal, solve for mu.
this brings me back to memories of AP Physics ahh xD
the assumptions: People on basil know physics well, and will not troll you with their answers.