Topic 2 - Mechanics

Definitions for Topic 2 - Mechanics: 2.1 - Motion 2.2 - Forces 2.3 - Work, energy and power 2.4 - Momentum and impulse

Newton’s first law

An object remains at rest or keeps moving at constant velocity unless an external force acts on it.

AKA. The law of inertia

Newton’s second law

The rate of change of momentum of an object is directly proportional to the resultant force applied and is in the direction of the resultant force

F=ma

Newton’s first law

An object remains at rest or keeps moving at constant velocity unless an external force acts on it.

AKA. The law of inertia

Newton’s second law

The rate of change of momentum of an object is directly proportional to the resultant force applied and is in the direction of the resultant force

F=ma

Newton’s third law

Every action (action force) has an equal and opposite reaction (reaction force).

(The two forces have the same magnitude and point in opposite directions)

Translational equilibrium

When an object is either at rest or moving at constant velocity it is in translational equilibrium

The net force acting on an object is zero

Work

When a force acts on an object and as a result the object moves over a distance, the force has done work

Energy

The capacity for doing work

Can be transferred, when being transferred work is being done

Can not be created or destroyed

Kinetic energy

The energy that an object has because of motion

Ek=mv^2/2

Elastic potential energy

Energy stored as a result of applying a force to deform an elastic object

Ep=kx^2/2

Gravitational potential energy

The energy that an object has because of its position in a gravitational field

Ep=mgh

Power

The rate of doing work/amount of energy transferred or converted per unit of time

Momentum

The product of the mass and the velocity of an object

Principle of conservation of linear momentum

If no external force acts on a system, momentum remains constant

Impulse

The product of force and time