Friction is a force that counters all kinds of motion. It occurs whenever two surfaces come into contact.

Which is the force that always acts against motion?

The force of friction always acts on all the moving objects and its direction is always opposite to the direction of motion.

What is an unbalanced force?

When two forces acting on an object are not equal in size, we say that they are unbalanced forces. a stationary object starts to move in the direction of the resultant force. ... a moving object changes speed and/or direction in the direction of the resultant force.