# Is Spring force a restoring force?

Yes, the spring force is a restoring force, because the force exerted by the spring is always in the opposite direction to the displacement. This is why there is a negative sign in Hooke’s law equation.

## Hooke’s law

According to Hooke’s law, the force required to stretch an elastic object such as a metal spring is directly proportional to the extension of the spring for small distances. The force exerted back by the spring is known as Hooke’s law.

Mathematically, Hooke’s law is commonly expressed as

F = –k.x

Where,

• F is the force
• x is the extension length
• k is the constant of proportionality known as spring constant in N/m