What do you use to measure frictional force?

Answer 1

The maximum frictional force acting on an object is found by the equation F = Fn * Fs, where Fn is the normal force acting on the object (by Newton's 3rd Law, Fn can equal the body's weight in magnitude) and Fs is the static friction property of the surface, usually determined by experiment or given. If the body is already in motion, F = Fn * Fk, where Fk is the kinetic friction. This is also a property of the surface determined by experiment. It is usually significantly less than the static friction. (This is why it is easier to push a heavy crate across the floor once you start to move it.) Example: The static friction of a desk is determined by experiment to be .5. What is the required horizontal force to be applied to a 10 N book in order to move it? 1) To move the book, the applied force must exceed the maximum frictional force acting on it. so Fapp > F. 2) Find F. F = Fn * Fs. F = (W of book)(.5) as Fs is given to be .5. By Newton's third law, the weight of the book equals the normal force on it from the desk. F = (10 * .5) The frictional force = 5 N. Therefore, you must apply a force greater than 5 N horizontally.

Answer 2

The maximum frictional force F on a body is given by:

F= UR

where U is the coefficient of friction

R is the normal reaction acting on the body

It is important to note that the above formula is true only on certain conditions which are:

either (i) The body is moving relative to the surface.

or (ii) The force applied on the motion parallel to the surface is equal to UR

For instance, when a force F' is applied on a stationary body parallel to the surface on which the body rests:

(i) If F'< UR, then F=F' and the body remains at rest

(ii) If F'=UR, then F=UR and the body still remains at rest

(iii) If F'>UR, then F=UR and the body moves with an acceleration produced by the resultant force (F'-F)

Answer 3

mass of object*acceleration (usually due to gravity-9.8m/s^2)*mu (friction constant for surface)

if the object is on a slope, you would multiply the force by the sine of the angle the normal force vector makes with the acceleration vector...

Answer 4

first, calculate the normal force on the object.

second, if the object is in motion find the coefficient of friction for the surface.

third, input the data (frictional force = coefficient of friction * normal force).

Answer 5

To find kinetic friction, you can use the conservation of energy. The kinetic energy plus the potential energy at some initial point in time will equal the sum of kinetic energy, potential energy, and thermal energy lost due to friction at a later point in time (in a closed system). The difference in mechanical energy between the two points in time will be the thermal energy. You can use this to find friction by the following relationship: Thermal energy = (coefficient of kinetic energy)(normal force)(distance). The coefficient of kinetic friction depends on the surface.

There is also a coefficient of static friction for a particular surface. This only applies when static friction is at its maximum, that is, when any additional force applied would send the body into motion. Static friction can be calculated if you know the other forces acting on the body. Since force = mass x acceleration, the frictional force will be precisely the amount needed to keep the acceleration at zero.

Answer 6

The Sum of all Net Forces is equal to Mass times Acceleration.

Also, force equals pressure times area.

Answer 7

Friction is the difference between the applied force and system acceleration.

Answer 8

Force is mass times acceleration.

Answer 9

U=fr