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The block brake consists of a pin-connected lever and friction block at B. The coefficient of static friction between the wheel and the lever is, μs = 0.3, and a torque of 5 N · m is applied to the wheel. Determine if the brake can hold the wheel stationary when the force applied to the lever is (a) P=30 N, (b) P=70 N.
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Chapter 8 Solutions
Engineering Mechanics: Statics, Student Value Edition Plus Mastering Engineering with Pearson eText -- Access Card Package (14th Edition)
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- The screw of the clamp has a square thread of pitch 0.16 in. and a mean diameter of 0.6 in. The coefficient of static friction between the threads is 0.4. Determine (a) the torque C0 that must be applied to the screw in order to produce a 28-lb clamping force at A; and (b) the torque required to loosen the clamp.arrow_forwardThe square-threaded screw 0f the C-clamp has a mean diameter of 8 mm and a pitch of 1.6 mm. The coefficient of static friction between the threads is 0.2. If the torque C=1.50Nm is used to tighten the clamp, determine (a) the clamping force; and (b) the torque required to loosen the clamp.arrow_forwardThe leather rein used to fasten the horse to the hitching rail weighs 3.5 oz per foot. The coefficient of static friction between the rail and the rein is 0.6. If a 34-lb force acting on the bridle is sufficient to restrain the horse, determine the smallest safe length L for the free end of the rein.arrow_forward
- The single-threaded screw of the floor jack has a pitch of 0.5 in. and a mean radius of 1.75 in. The angle of static friction is 8.5. (a) Determine the couple C that must be applied to the screw to start lifting a weight of 4000 lb. (b) What is the couple required to start lowering the weight?arrow_forwardThe single-plate clutch transmits the torque C from the input shaft on the left to the output shaft on the right. Compression springs between the clutch housing and the pressure plate provide the necessary pressure on the friction surface. The splines prevent the clutch plate from rotating relative to the output shaft. If Ri=4 in. and R0=9 in., determine the total force that must be applied to the pressure plate by the springs if the clutch is to transmit a torque of C=56lbft when it is new.arrow_forwardTwo hemispheres having an inner radius of 2 ft and wall thickness of 0.25 in. are fitted together, and the inside pressure is reduced to -10 psi. If the coefficient of static friction is ms = 0.5 between the hemispheres, determine (a) the torque T needed to initiate the rotation of the top hemisphere relative to the bottom one, (b) the vertical force needed to pull the top hemisphere off the bottom one, and (c) the horizontal force needed to slide the top hemisphere off the bottom one.arrow_forward
- A 60-kg cabinet is mounted on casters that can be locked to prevent their rotation. The coefficient of static friction between the floor and each caster is 0.35. 3. If h = 600 mm, determine the magnitude of the force P (in N) required to move the cabinet to the right if the casters at A are locked and the casters at B are free to rotate. (ANSWER: 72.5)arrow_forwardCouple forces of F= 35 N are applied to the handle of the machinist's vise. The guide at B is smooth. The single square-threaded screw has a mean radius of 6 mm and a lead of 8 mm , and the coefficient of static friction is μs= 0.27.arrow_forwardA 0.8 lb roll of paper is suspended from a wire hanger so that it rests against the wall. The hanger has a negligible weight and the bearing O can be considered as frictionless. The two ends of the hanger can be treated as pin joints. Determine the force P required to start turning the roll if theta = 37 degrees and the coefficient of static friction is 0.29.arrow_forward
- roll of paper has a uniform weight of 2kN and is suspended from the wire hanger so that it rests against the wall. If the hanger has a negligible weight and the bearing at O can be considered frictionless, determine the force P needed to start turning the roll if = 30°. The coefficient of static friction between the wall ܬܐ and the paper is µ = 0.3.arrow_forwardThe pickup truck pulls the wooden crate, as shown in Figure 2. The truck has a mass of 1.25 Mg and a center of mass at G. The coefficient of static friction between the truck's wheel and the ground is µ = 0.5, and between the wooden crate and the ground is µs' = 0.4. Determine the greatest weight of the wooden crate the pickup truck can pull if: a) the truck has rear-wheel drive while the front wheels are free to roll, and b) the truck has four-wheel drive.arrow_forwardA safety device used by workers climbing ladders fixed to high structures consists of a rail attached to the ladder and a sleeve that can slide on the flange of the rail. A chain connects the worker’s belt to the end of an eccentric cam that can be rotated about an axle attached to the sleeve at C. Determine the smallest allowable common value of the coefficient of static friction between the flange of the rail, the pins at A and B , and the eccentric cam if the sleeve is not to slide down when the chain is pulled vertically downward.arrow_forward
- International Edition---engineering Mechanics: St...Mechanical EngineeringISBN:9781305501607Author:Andrew Pytel And Jaan KiusalaasPublisher:CENGAGE L