Write different type of common forces.

Explanation

Gravitational force electric force and electromagnetic force are field force push or pull are other force in mechanics are contact forces.
Component of constant force normal to surface is called rection (R= N)
Component of contact force parallel to surface is called friction force.

When spring is subjected to external force restoring force developed in the spring which tries to regain original shape. this restoring force is proportional to change in length which is given by equation f=- kx. Negative f indicate that restoring force is in opposite direction to displacement .