The 81-lb force Pis applied to the 190-lb crate, which is stationary before the force is applied. Determine the magnitude and direction of the friction force Fexerted by the horizontal surface on the crate. The friction force is positive if to the right, negative if to the left. Assume u, = 0.41, Hx = 0.33.

The 81-lb force Pis applied to the 190-lb crate, which is stationary before the force is applied. Determine the magnitude and direction of the friction force Fexerted by the horizontal surface on the crate. The friction force is positive if to the right, negative if to the left. Assume u, = 0.41, Hx = 0.33.

International Edition---engineering Mechanics: Statics, 4th Edition

4th Edition

ISBN:9781305501607

Author:Andrew Pytel And Jaan Kiusalaas

Publisher:Andrew Pytel And Jaan Kiusalaas

Chapter7: Dry Friction

Section: Chapter Questions

Problem 7.55P: A wedge is used to prop up the 6000-lb block of marble. The wedge angle is =30, and the angle of...

See similar textbooks

Similar questions

The 600-lb cable spool is placed on a frictionless spindle that has been driven into the ground. If the force required to start the spool rotating is F = 160 lb, determine the coefficient of friction between the ground and the spool. Neglect the diameter of the spindle compared to the diameter of the spool.
The 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.
The two uniform sheets of plywood, each of length L and weight W, are propped as shown. If the coefficient of static friction is 0.5 at all three contact surfaces, determine whether the sheets will remain at rest.
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?
The normal pressure acting on the disk of the sander is given by p=(4/3)+(r2/6), where p is the pressure in pounds per square inch (psi) and r represents the radial distance in inches. Determine the torque C required to operate the sander at constant speed if the kinetic coefficient of friction for the surface being sanded is 0.86.
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.
Two identical chairs, each weighing 14 lb, are stacked as shown. The center of gravity of each chair is denoted by G. The coefficient of static friction is 0.2 at B (the contact point between the chairs) and 0.35 at A, C, and D. Determine the smallest force P that would cause sliding.
The 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.
The 40-lb spool is suspended from the hanger GA and rests against a vertical wall. The center of gravity of the spool is at G and the weight of the hanger is negligible. The wire wound around the hub of the spool is extracted by pulling its end with the force P. If the coefficient of static friction between the spool and the wall is 0.25, determine the smallest P that will extract the wire.
The cone clutch transmits the torque C through a conical friction surface with cone angle . The inner and outer radii of the friction surface are a and b, respectively. The left half of the clutch is keyed to the shaft, and the right half drives a machine (not shown) through a gear attached to its outer rim. Assuming uniform pressure on the friction surface, show that the maximum torque that can be transmitted by the clutch is
Calculate the horizontal force P required to push the 85-lb lawn mower at constant speed. The center of gravity of the mower is at G, and the coefficients of rolling resistance are 0.12 for the front wheels and 0.18 for the rear wheels.
A wedge is used to prop up the 6000-lb block of marble. The wedge angle is =30, and the angle of static friction is s=12 between all contact surfaces. Determine the smallest force P that would prevent the wedge from sliding out.