1. Balanced Forces
If the forces on an object are balanced it will either remain stationary or move at the same speed in the same direction.
A stationary object will have two equal and opposite forces acting on it; its weight and the upwards force (reaction) from the surface.
Balanced forces

2. Forces on a car
Forces on a car

3. Forces
Forces

4. Balanced Forces
Balanced Forces

5. Unbalanced Forces
If the forces on an object are unbalanced it will either speed up, slow down, change shape or change direction.
The greater the unbalanced force, the greater the change in speed, direction or shape.
Unbalanced forces

6. Unbalanced forces
Unbalanced forces

7. Balanced & Unbalanced forces

8. Balanced & Unbalanced forces

9. A skydiver will initially accelerate due to the force of gravity.
Terminal Velocity
A skydiver will initially accelerate due to the force of gravity.
Air resistance increases until it balances the gravitational forces.
When the forces are balanced the skydiver will have reached terminal velocity.
Terminal Velocity

10. Sky diving
Sky diving

11. Sky diving
Sky diving

12. Inertia is the reluctance of an object to change its speed.
The heavier an object, the greater the unbalanced force needed to accelerate it or decelerate it.
Inertia

13. Inertia
Inertia

14. Friction is a force which acts when two objects are rubbed together.
Friction acts in the opposite direction to movement.
Friction causes objects to heat up and also causes their surfaces to wear away.
Car tyres could not grip the road without friction.
Friction is used in brakes.
Friction

15. Friction
Friction

16. Friction
Friction

17. Wordsearch
Wordsearch

18. Quiz
Quiz