Does increasing the load change the coefficient of static friction or kinetic friction?
926087
No, it won't change.   It's an inherent property that depends on the block and the ramp.  Putting more load on it won't change this.
2716
The coefficient of friction is the ratio of the force needed to push an object and make it slide divided by the force downward on the object (e.g., weight) resisting motion.  It is used to determine the amount of force that is needed to make a smooth surfaced object of one material slide on a smooth surface of the same or a different material.  For every combination of materials there is a specific coefficient of friction.  Once calculated, the coefficient can be used for various loads (size of object).  Ice on teflon has one of the lowest coefficients of friction.  If you place an object on a plank and raise one end almost every object will slide before you reach an angle of 45 degrees.  Objects that have an adhesive property or are especially rough or have cogs will not have true coefficients of friction.  Once the coefficient of friction is known for a combination of materials (e.g., as determined in a lab) it can be used in many mechanical calculations where friction is present although the motion is more complicated than sliding along a floor.\n\nAn extra effort is sometimes needed to get an object to slide initially that is greater than steady state friction and that is sometimes called stiction.
898087
Conceptually, force is defined by Newton's first law.  An external net force will change the direction of motion of an object.  An object will tend to move at a constant velocity in the same direction when there is no net force acting on the object.  Force changes the motion of an object.\n\nFriction is basically a force that acts on an object opposite the direction of an applied force or the direction of motion depending on the situation.\n\nStatic friction is the friction caused by a stationary object and is related to the amount of force you need to put on an object at rest to start motion.  If I want to move my desk, there is a certain amount of force I must put on the desk before the desk moves.  \n\nDynamic (or kinetic) friction is the friction caused by a moving object.  It is related to the amount of force needed to keep an object moving at a constant velocity.  If I am driving down the highway and set my cruise to 65 mph, my tires must put some amount of force on the highway to keep me moving at a constant velocity.  \n\nI am not sure what your teacher means by dynamic friction minus static friction as this is not a useful physical quantity.
944360
It's coefficient of friction is 0.1, which is the lowest of any solid.\n\nPS Go to wiki
981131
Sliding friction is the friction that an object has while it's moving.\n\nAn eraser has the most sliding friction.\n\nStatic friction is the resistance of an object from movement. I suppose since an eraser has the most sliding friction, it will also have the most static friction. that or a paperback book just because it's heavier.\n\nit really depends on the coefficient of friction. \n\nI should say that the eraser will have the highest coefficient of frictions, but the paperback book will have the highest overall friction just because of it's weight.
962433
The  kinetic energy of the ball is increased from 1.4 J to 6.5J by the work done on it.\n\nThe gain in kinetic energy is 6.5 - 1.4 = 5.1 J\n\nWork done on the ball = gain in kinetic energy = 5.1 J.
696645
Nice trick, combining multiple questions into one. I'll answer one q, no. 3.\nThe 300N force along the slope doesn't contribute to the normal force so has no effect on friction. The normal force is m*g*sin(slope) = 100 * 9.81 * 5/20. Your picture\nhttp://i34.photobucket.com/albums/d130/MATTRAINES/q4.jpg?t=1164668264\ndoesn't give a value for coefficient of friction, so if we assume it's 1, then Ff = the normal force.
574667
You need to specify the other surface when asking for the coefficient of friction.  For example, sneakers and gym floors.
49028
Yes the discharge coefficent must change as with the increase in the diameter the viscous forceacting in the center of the pipe will be reduced resulting in a higher discharge and a higher discarge coefficent
676957
E = 1/2 M V^2 where V is the velocity.  Either we need to know the distance of travel of the load or the speed of the vibrating load.\n\nA load  hitting the surface 3 times a second going back and forth 1 ft each way will exert greater energy than a load traveling only 1 inch 3 times a second.\n\nTherefore, if the distance of travel is "d"\nE= 1/2 [M (df)^2]
882649
First solve for the force of friction between the block and the table using the formula,\n\nf=uR, where f is the force of friction, u the coefficient of static friction, and R is the force normal to the table. R therefore is the weight of the block equal to 31g.\n\nf=0.425*31*9.8\n =129.1N\n\nThe weight of the sand added to the bucket plus the weight of the bucket itself should be just slightly equal to 129.1N so that the system will begin to move. At that point, however, the block will begin to accelerate because the force of friction acting on it will no longer be static friction but kinetic friction, which is lower in magnitude. Thus there will be a net force equal to 129.1 minus the force of kinetic friction on the block. Thus,\n\nNet force, F=129.1-0.320*31*9.8\n                 =129.1-97.2\n                 =31.9N\n\nF=ma, where F is our net force of 31.9N, m the total mass of block plus mass of sand and bucket, and a is the acceleration of the system.\n\nMass of sand and bucket=129.1/9.8\n                                    =13.2kg\nSubstitute known values:\n\n31.9=(31+13.2)a\na=31.9/44.2\n  =0.72m/s^2
260289
Stephen_mgi is correct.\n\nForce x distance moved is the work done.\n\n Suppose a 10 N force is moved through a distance 5m the work done is 50 joule.\n\nThe same work can be done in many number of ways; for example  5 N force when moves through 10 m or 1N force moves through 50 m; or 25N force moves through 2m etc.\n\nThus when force is reduced distance is increased. Any one will feel it convenience to reduce the force rather than to give huge force and jump up to go to a higher place.\n\nIn the stair case when we increase the distance by walking in a diagonal way we reduce the force and feel it easy.\n\nThe stair case is a simple machine which is designed at a slope. \n\nBy walking diagonally we still reduce the slope to our convenience.
835350
The coefficient of friction is the ratio between the force pressing two objects together and the force of friction between them. In the case of of sliding friction, this is literally the ratio of two forces. However in the case of static friction, this is the ratio of one force (the force pressing the two objects together, also called the normal force) to the maximum force that can be supplied by static friction. The actual force may be less than that. For instance, if the force tangent to the surface is less than the coefficient of friction times the normal force, the actual force of friction will be equal and opposite to the tangent force, and the object won't move.\n\nAnyway, the question asks whether there are any materials for which the coefficient of friction is greater than 1. A simple glance at a reference table, such as the one linked below, reveals the answer is yes.
44667
You have a contradiction in your statement.  Static friction implies no movement but velocity is movement.  \n\nIf you mean the velocity of an object in dynamic equilibrium has a result of a frictional force (kinetic though) like sliding a block across the floor then you have to know the amount of work put into the system.  Then use work-kinetic energy theorem.
399579
It would screw up a lot of calculations and other assigned physical values. Since no friction at all is 0 you would be claiming less friction than none. It is set up the way that it is for much the same reason that there are limits to aerodynamic lift and other forces that are nonsensical when allowed to become either negative or larger than one.
515562
Friction, Heat generated to name 2 reasons.
118752
The fricional force between an object and a surface is dependent on two things,\nthe coefficient of friction between the two surfaces and the normal force exerted by the surface on the object.\nIf you increase either of these, the frictional force is increased, likewise, if you decrease (or make zero) any of these, the frictional force is less (or zero).