The force that keeps object at rest is known as static friction. It is equal to the product of normal force and coefficient of static friction.
Equation for static friction = Normal force Coefficient of static friction
Formula: Fs = N μs
Where N is normal force and sis coefficient of static friction
Static frictional force can be calculated by using normal force and coefficient of static friction.
Fs=N μs
Let Normal force = 50 N
Coefficient of static friction μs= 0.2
Plugging value of N and μs in the formula we get static frictional force.
Fs=N μs
= 500.2
=10 N
In this way we have solved for static frictional force.