A 15.5 m uniform ladder weighing 520 N rests against a frictionless wall. The la

Question

A 15.5 m uniform ladder weighing 520 N rests against a frictionless wall. The ladder makes a 65.0° angle with the horizontal.

(a) Find the horizontal and vertical forces the ground exerts on the base of the ladder when an 810 N firefighter is 3.80 m from the bottom.

Magnitude of the horizontal force
_____ Direction

Towards the wall?

Away from the wall?

up or down?

Magnitude of the vertical force
_____ Direction

up or down    

(b) If the ladder is just on the verge of slipping when the firefighter is 9.40 m up, what is the coefficient of static friction between ladder and ground?

______

Explanation / Answer

a)

Using equilibrium of torque about A

F2 Sin65 (L) = 520 Cos65 (L/2) + 810 Cos65 (3.80)

F2 Sin65 (15.5) = 520 Cos65 (15.5/2) + 810 Cos65 (3.80)

F2 = 213.84 N

away from wall

Using equilibrium of forces in vertical direction

F1 = 520 + 810

F1 = 1330 N

Up

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.