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Torque Equilibrium problem

  • Thread starter vipertongn
  • Start date
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1. Homework Statement

A uniform ladder of length L and mass m1 rests against a frictionless wall. The ladder makes an angle θ with the horizontal.
(a) Find the horizontal and vertical forces the ground exerts on the base of the ladder when a firefighter of mass m2 is a distance x from the bottom. (Answer using m_1 for m1, m_2 for m2, theta for θ, g for gravity, and L and x as necessary.)
horizontal

(b) If the ladder is just on the verge of slipping when the firefighter is a distance d from the bottom, what is the coefficient of static friction between ladder and ground?


2. Homework Equations

Net Fy = 0
Net Fx = 0
Net T = 0

3. The Attempt at a Solution

I tried n_g-m_1*g-m_2*g as the answer for the vertical force because the ladder has a normal force that is exerted in reaction to the two gravitational forces from the ladder itself and the firefighter. I believe that this isn't the correct way to input it.

for the force for horizontal I know its the frictional force minus the normal force from the wall. however I don't know how to input it using hte variables they want.
 

tiny-tim

Science Advisor
Homework Helper
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A uniform ladder of length L and mass m1 rests against a frictionless wall. The ladder makes an angle θ with the horizontal.
(a) Find the horizontal and vertical forces the ground exerts on the base of the ladder when a firefighter of mass m2 is a distance x from the bottom. (Answer using m_1 for m1, m_2 for m2, theta for θ, g for gravity, and L and x as necessary.)
horizontal

(b) If the ladder is just on the verge of slipping when the firefighter is a distance d from the bottom, what is the coefficient of static friction between ladder and ground?
Hi vipertongn! :smile:

Yes, the normal force will be equal and opposite to the other vertical forces.

To find the horizontal forces, take moments about some convenient point. :wink:
 

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