# Forces definitions Flashcards

Definition of Mass

Mass is defined as the amount of matter in an object and is measured in kilograms

Definition of Weight

Weight is defined as the force acting on an object due to the pull of gravity and is measured in Newtons

Definition of Friction

Friction is the force which opposes motion

Newton’s first law

Newton’s first law states: an object will remain at rest or continue in uniform motion unless acted on by a resultant force.

Newton’s second law

When an object is acted upon by a resultant force it will accelerate in the direction of the resultant force. The size of the acceleration is proportional to the resultant force and inversely proportional to the mass.

Hooke’s law

The extension of the spring is directly proportional to the load applied provided the limit of proportionality is not exceeded.

Centre of gravity

The point on an object through which all of its weight appears to act.

Conditions of stability.

An object is stable if the vertical line from the centre of gravity falls inside its base.

Moments

The product of the force and its perpendicular distance from the pivot.

Principle of moments

When an object in equilibrium the sum of the clockwise moments must be equal to the sum of the anticlockwise moments about the same pivot.