2. At a construction site, a 65.0-kg bucket of concrete hangs from a light cable that passes over a light, frictionless pulley and is connected to an 80.0-kg box on a horizontal roof as shown below. A 50.0-kg bag of gravel rests on top of the box. The coefficients of friction between the box and the roof are also shown. Gravel Box His 0.700 Mk = 0.400 = Concrete A. Find the friction force on the bag of gravel and box. B. Suddenly a worker picks up the bag of gravel. Find the speed of the bucket after it has descended 3.00 m from rest.

4. In the following figure, a box of m₂= 2.0 kg appears on an inclined plane with a coefficient of kinetic friction of 0.15 that makes an angle of 30 degrees. It is connected by a string of negligible mass to a box m₁= 0.5 kg lying on a horizontal friction surface with a coefficient of kinetic friction of 0.15. A force of 2.3 N to the right is applied to the box m₁. Determine: a. b. The acceleration of the boxes and the tension in the string. The value of the force applied so that the boxes move at a constant speed. 111 m₂

A sled is on a horizontal surface and a rope with tension T is pulling on it at an angle 0 above the horizontal. The sled had mass M and does not move due to the frictional force. In this case the coefficient of friction is µ̟. In terms of the variables given and g, what is the magnitude of the frictional force in this case? Select one: a. H, Mgsino b. Tcose O c. Tsin0 O d. H, Mgcos0

2.  A chain consists of identical links, each with a mass of 2.5 kg. You grab the top link and hold the chain at rest so that it hangs vertically.    a)  Draw a free body diagram of the bottom three links (labeled 1, 2, 3). Label all forces and use double subscript notation to denote which object exerts the force and which object is experiencing the force.   b)  Find the magnitude of the force exerted on link 1 by link 2, in Newtons.   c)  Find the magnitude of the force exerted on link 2 by link 3, in Newtons.