(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A painter wishes to know whether or not she can safely stand on a ladder. The ladder has a mass M1 = 14 kg which is uniformly distributed throughout its length L = 8.6 m. The ladder is propped up at an angle theta = 52o. The coefficient of static friction between the ground and the ladder is mus = 0.45, and the wall against which the ladder is resting is frictionless. Calculate the maximum mass of the painter for which the ladder will remain stable when she climbs a distance d = 5.2 m up the ladder. (The painter's mass might be so low that only Lilliputian painters can safely ascend the ladder.)

2. Relevant equations

Fric = Us*N

F=m*a

Torque= r *(dot)F

3. The attempt at a solution

Right now I'm just looking for a poke in the right direction. I can't even figure out where to start. I know that the frictional force is going to be at a maximum when the weight is at the maximum. I think that the normal force will be the 137.2 N from the ladder + 9.8*the mass of the painter. But how do I figure out what the maximum Fric will be? I also know that the problem has to do with torque. Any help is appreciated, I'm new so I'm sorry if I didn't give it enough effort but I've been staring at it and my book for about an hour to an hour and a half and couldn't get anywhere.

Thanks,

Matt

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Friction/Torque question.

**Physics Forums | Science Articles, Homework Help, Discussion**