Physics Year 10 Term 3: Forces, Energy and Work

Newton's First Law

Objects tend to continue travelling at constant velocity unless acted upon by an unbalanced force.

Balanced Forces

Forces acting on an object are equal and opposite, resulting in no overall force.

Law of Inertia

Objects have inertia dependent on their mass; more mass means more inertia- an object at rest stays at rest, and an object in motion stays in motion at a constant speed and in a straight line, unless an unbalanced external force acts upon it

Newton's Second Law

F = ma, where acceleration is directly proportional to force and inversely to mass.

Newton's Third Law

Forces always come in pairs that act in equal and opposite directions.

Unbalanced Forces

Forces are not equal and opposite, which can cause an object to accelerate.

Weight (W = mg)

The gravitational force acting on an object, equal to mass times gravitational field strength.

Gravitational Potential Energy (Eg)

Eg = mgh, the energy possessed by an object due to its mass and height above Earth's surface.

Balanced Forces on Moving Objects

A balanced force does not stop a moving object; it continues moving at a constant velocity.

Total Mechanical Energy (Em)

Em = Ek + Eg, the combined amount of kinetic and gravitational potential energy.

Kinetic Energy (Ek)

Ek = ½mv², the energy possessed by an object due to its motion.

Work (W = Fs)

Energy transferred when a force causes an object to move through a certain distance.

What is energy?

Energy is the ability to work. Energy can not be created or destroyed, it can only be transferred or transformed.