FOrces

The Net Force

• There is usually more than one force acting on an object, so we combine these forces to calculate the net force (Fnet).
• The net force will tell us if an object is stationary or moving
• We add forces acting in the same direction and subtract forces acting in the opposite direction

Balance and Unbalanced Forces

• If opposing forces are balanced the net force will be zero and the object will be stationary or traveling at a constant speed
• If the opposing forces are unbalanced there will be a net force and the object will accelerate in one direction

F = ma

When forces are unbalanced it will make an object accelerate.

We can calculate the force of an object if we know its mass (m) and its acceleration (a)

• Mass is measured in kg
• Acceleration is measured in ms-2

Success Criteria

• I am able to define what a force is
• I am able to draw a force diagram and calculate the net force
• I am able to explain the relationship between force, mass and acceleration

Friction

• Friction is a force which is created as soon as something tries to slide past something else

Is it Mass or Weight?

Mass is the amount of material in an object

Weight is gravity's force (10Nkg-1) acting upon its mass

weight = mg

Weight is measured in Newtons (N)

Success Criteria

Forces

• Forces are pushes or pulls
• Forces can change the motion of an object - they can change the speed and direction
• A force has a size and a direction
• Forces are measured in Newtons (N)

• I am able to explain the difference between mass and weight
• I am able to calculate the weight of an object
• I am able to explain the importance of friction and air resistance
• I am able to define Pressure and explain its relationship with Force and area

FOrces