Chapter 8, Problem 114P

Fpull Ꮎ A person, weighing 115 lb, is being lifted by a rope thrown over a tree branch as shown (drawing not to scale). If the static coefficient of friction between the rope and the tree branch is μs = 0.60, and the 0 = 45°. Determine the pulling force required to start lifting the person and the pulling force required to keep the person from falling? Pulling force to lift the person: Pulling force to keep the person from falling: lb lb

The high strength, square-threaded bolt that holds the three plates together has a nominal diameter of 1 in. The coefficient of friction is us = 0.36. The mean diameter of the thread is 0.94 in. The lead of the bolt is L = 0.160 in. Neglect friction between the nut and the washer. Determine the torque one must apply in in. Ib to the nut to induce a tension of 47,500 lb. (Enter the magnitude.) in. · Ib When that tension is achieved, determine the torque in in. · Ib required to loosen the bolt. (Enter the magnitude.) in. • Ib

Q3: The coefficient of static friction [10 M] 300 mm -700 mm between the drum and brake bar is µs = 0. 4. If the moment M = 35 N : +125 mm 500 mm m, determine the smallest force P that needs to be applied to the brake bar in order to prevent the drum from rotating. Also determine the corresponding horizontal and vertical components of reaction at pin 0. Neglect the weight and thickness of the brake bar. The drum has a mass of 25KG.

Q3 the forle P = looN causes the massless block (A) to just about to move along horizontal surface. Determine the static coefficient of friction (s) between Block(A) and the surface. Im P=100 um

The figure shows a bar in equilibrium position resting on the floor at point A and on the wall at point B. If the mass of the bar is m and the angle it makes with the floor is θ = π/6, find the magnitudes of the frictional and normal forces at points A and B.

Box A weighs 1000N and has a height of H1=3m and width W1=2m. Box B weighs 800N.  the static friction coefficient between the boxes is uA=0.7 and the static friction coefficient between box B and the ramp is uB=0.5.  Find the max allowable angle for the following instances where no motion occurs, box A and B remain stationary. 1) Box A slides, Box B remains stationary 2) Box A tips, Box B remains stationary 3) Box B slides, Box A remains stationary on block B

1) Determine the average braking torque to be applied to stop the vehicle of mass 1.5 ton is movingdown the hill at a slope of 1:7 at 60 kmph and the vehicle is to be stopped at a distance of 50 m.Take the diameter of the vehicle tyre as 500 mm. If the friction energy is momentarily stored in a20 kg cast iron brake drum, what is the average temperature rise of the drum? The specific heat forcast iron may be taken as 520 J/kg ˚C.

A 70 lb-bag of rice is being pulled by a person by applying a force F at an angle 0. The force required to drag the bag is F(0) = (70p)/(µsine + cose) where u = 0.35 is the coefficient of friction. Determine the maximum F by creating a vector for the angle with elements ranging from 5° to 35° and spacing of 0.01 and use the built-in function max. The maximum F is

A tank of water sits on a cart with frictionless wheels as shown. The cart is attached to a mass and the coefficient of static friction of the mass with the ground is µ = 0.50. There is a gate blocking the tank exit and the vertical distance between the free surface and the tank exit is 2 m. The tank exit makes a 60o angle with the horizontal. The tank exit diameter is 50 mm. Now, the gate blocking the tank exit is removed. Find the mass, M, that is sufficient to hold the cart stationary.State all your assumptions clearly.