A ladder leans against a frictionless vertical wall. If the ladder is uniform, has a mass of 5kg, and 2.5m long, then what is the friction on the bottom of the ladder when it sits at an angle of 75◦ with a 85kg person standing 1m from the top?

A 25-ft chain with a weight of 30 lb is suspended between two points at the same elevation. Knowing that the sag is 10 ft, determine (a) the distance between the supports, (b) the maximum tension in the chain.

A 60 kg painter is on a scaffold supported from above by ropes.  The scaffold has a mass of 25 kg and is uniformly constructed.  There is a 4.0 kg pail of paint off to one side, as shown in the figure.  Can the painter walk safely to both ends of the scaffold? If not, which end(s) is dangerous and how close to the end can he approach safely?

You can probably stand flatfooted on the floor and then rise up and balance on your tiptoes. Why are you unable do it if your toes are touching the wall of your room?

A ladder of negligible mass composed of two L-long rails that are hinged at the top, is placed on top of a frictionless floor. A metal bar, connecting both rails halfway up the ladder is placed so that the two rails make an angle of 0 = 43.0 at the apex. Lastly, a M = 4.30 [kg] block is placed 2/3 of the way up the ladder, as shown. 213 L Ө L H # A) what is the magnitude of the tension in the metal bar? B) What is the magnitude of the normal force exerted on the bottom right side of the ladder? C) What is the magnitude of the normal force exerted on the bottom left side of the ladder? D) What is the magnitude of the force the right side of the ladder exerts on its left side?

A 60lb child and a 150lb adult are each holding 30lb weights and balancing on a seesaw. (a) If the child sits 6 feet from the pivot point, how far from the pivot point must the adult sit? (b) Next both drop their 30lb weights. If the child stays 6 feet from the pivot point how far from the pivot point, must the adult sit now?

A uniform rod AB of weight 500 N and length 4.0 m is supported at two points P and Q as shown below. AP = QB = 0.80 m. A man of weight 800 N is walking from Q to B. Find the maximum %3D %3D distance x from Q the man can walk before the rod topples about Q. P Q A 1 -| × |- O 0.4 m O 0.8 m O 0.75 m O 0.6 m

A 50 N hand and forearm are held at a 35° angle to the vertically oriented humerus. The CG of the forearm and hand is located at a distance of 12.5 cm from the joint center at the elbow, and the elbow flexor muscles attach at an average distance of 2.5 cm from the joint center. (Assume that the muscles attach at an angle of 35° to the forearm bones.) How much force must be exerted by the forearm flexors to maintain this position?

a 8-53.. A lantern of weight W is suspended at the end horizontal bar of weight w and length L that is supported by a cable that makes an angle with the side of a vertical wall. Assume the weight of the bar is at its center. (a) Derive an equation for the tension in the cable. (b) Calculate the tension in the cable for a bar of weight 28 N and length 1.5 m, plus a lantern of weight 85 N, and the cable making a 37° angle to the vertical. 40² D