What is Static friction?
Static friction is defined as the frictional force which acts between the two surfaces when they are in the rest position with respect to each other.
Some Examples of Static friction are,
- Pushing heavy objects such as trains, buses, etc.
- Clothes hanging on the hanger.
- Car parked on a slope.
- Man standing on the mountain.
Mathematically, static friction is defined as,
Fs = μsη
where,
- Fs is the Static Frictional Force,
- μs is the coefficient of static friction,
- η is the Normal force (= mg),
- m is the mass of the object, and
- g is the acceleration due to gravity (= 9.8m/s2).
Difference between Static Friction and Dynamic Friction
Friction is defined as the force that opposes the motion between any surfaces, fluid layers, and any other material in contact with each other. Friction is produced due to the irregularities between the surfaces. It produces heat. It depends on the nature of the surfaces. Friction always acts between any two contact surfaces of bodies. Friction is a contact force.
For Example, rubbing our hands generates heat. So friction is produced while rubbing our hands. While driving a car, if we use the brake to stop or slow down the car, friction is produced between the brakes and wheels, which makes the car slow down or stop.
Mathematically, friction is given as,
F = μη
where,
- F is the Frictional Force,
- μ is the coefficient of friction,
- η is the Normal force (= mg),
- m is the mass of the object, and
- g is the acceleration due to gravity (= 9.8m/s2)
Unit Of Friction
Since friction is considered to be a force therefore the SI unit of Friction is Newton (N).
According to the position of the objects or materials in contact, friction can be categorized into two,
- Static Friction
- Dynamic Friction
Let’s now discuss the difference between the two, starting with understanding their basic concepts as,