Lab Frictional Forces (1)

A rough board 10 meters long lies horizontally on the ground. A box is placed at the centre of the board. One end of the board is then slowly raised above the ground. When the lifted end reaches a vertical height of 6 meters, the box just begins to slide. The coefficient of static friction is:

A 68 kg credenza is being pushed to move it. Due to use of sliders on the right side "feet," the coefficient of static friction at those feet, labeled B, is .2 while the coefficient of static friction at the feet labeled A is .4. Assuming impending motion, find the minimum force needed to move the credenza. Draw a clear and complete FBD before setting up your equations. Make sure your equations are clear before solving them! 0.8 m 0.7 m 0.6 m 0.6 m

A block of concrete weighs 20 kg, it takes 40 N to start the block sliding on a concrete floor and 10 N to maintain sliding.  Calculate the Static coefficiant of friction and calculate the kinetci coefficiant of friction  My question is; what is the coefficiant of static and kinetic friction. Ive read throught the book and cant seem to find anything that explains it. I found a formula which reads F = Static coefficiant multiplied by the weight of the block. But that doesnt tell me exactly what the coeffciant of each is, Is it a constant? or does it vary based on the item being moved? Thank you.

A block of mass M = 539.0 g sits on a horizontal tabletop. The coefficients of static and kinetic friction are 0.549 and 0.391, respectively, at the contact surface between table and block. The block is pushed on with a 13.6 N external force at an angle \theta with the horizontal. a) What angle with respect to the horizontal will lead to the maximum acceleration in horizontal direction of the block for a given pushing force? (Give your answer in degrees and use the unit "deg") b) What is the value of this maximum horizontal acceleration?

DD=25

A block whose weight is 40 N rests on a horizontal surface. The coefficient of static friction between the block and the surface is 0.50. A string is attached to the block. The string is pulled horizontally with a force of 15 N. Which one of the following statements is correct? The magnitude of the force of friction on the block is 5 N. The magnitude of the force of friction on the block is 15 N.     The force of friction cannot be determined because the coefficient of kinetic friction is not given. The magnitude of the force of friction on the block is 20 N. The force of friction cannot be determined because the normal force of the surface on the block is not known. 2. A block is sliding at constant speed down a ramp. Decide whether each of the following statements is true or false. (a) The net work done on the block as it slides equals zero. True or False     (b) The normal force does zero work on the block as it slides. True or False     (c) The friction force does positive…

A 75 N force, inclined at an angle a = 45° as shown in Figure 3.5, pulls a 100 N block. The coefficient of static friction between the block and the floor is 1.3, and the coefficient of kinetic friction is 1.1. Determine the friction force between the block and the floor.

QI: A box weighing 100 N is at rest on a horizontal floor. The coefficient of the static friction F sin 6 between the box and the floor is 0.4. What is the smallest force exerted eastward and upward at an angle of 30° with the horizontal that can start the box in motion? 0 34F F cos 0

I need help with this Please help me

The pulley of Fig. wheel that fits loosely over a t in.-diameter shaft. A rope passes over the pulley and is attached to a 50-lb weight. The static and kinetic coefficients of friction between the consists of a 4-in.-diameter pulley and the shaft are 0.35 and 0.25, respectively. The weight of the pulley is 2 lb. The rope being pulled makes an angle 8 = 90° with the horizontal. Determine the force necessary to Just start lowering the weight. P

A crate, in the form of a cube with edge lengths of 1.2 m, contains a piece of machinery; the center of mass of the crate and its contents is located 0.123 m above the crate's geometrical center. The crate rests on a ramp that makes an angle 0 with the horizontal. As 0 is increased from zero, an angle will be reached at which the crate will either tip over or start to slide down the ramp. If the coefficient of static friction Hs between ramp and crate is .55, (a) does the crate tip or slide? (b) At what angle 0 does this occur? If us = 0.94, (c) does the crate tip or slide? (d) At what angle 0 does this occur? (Hint: At the onset of tipping, where is the normal force located?)

4. Explain how a distributed normal force can be represented by a point force that moves as the distribution of a normal force shifts. 5. Explain the concept of dry friction and show how to analyze the equilibrium of rigid bodies subjected to this force. (CO-5) 6. Understand the applications of frictional force analysis on wedges, screws, belts, and bearings. (CO-5)

A 200 lb block is in contact with a plane inclined at 30 degrees to the horizontal. A force P, parallel to and acting up the plane, is applied to the body. If the coefficient of static friction is 0.20, find: a. the value of P to just cause the motion to impend up the plane b. the value of P just to prevent motion down the plane c. the magnitude and direction of the friction force F if P= 80 lbs

A box rests on a horizontal plane. The plane is slowly tilted so that the angle between the surface and the horizontal increases to 20 degrees, at which point the box begins to slip. what is the coefficient of static friction between the box and the surface to 2 s.f.?