Newton's laws of motion

You will have heard these before in School no doubt, here they are.

1. An object in motion will stay in motion, an object will likewise remain at rest (still) unless acted upon by an unbalanced force.

2. The greater the mass of an object the more energy needed/required to move the object in a given direction.

3. For every action, there is an equal and opposite reaction.

So here are explanations of the laws using scenarios.

1. If you let go of something that is moving, such as a shopping trolley (or anything with wheels), it will keep moving in a given direction before it hits something or looses momentum. This law is all about INERTIA. Inertia is the ability to resist change, as in practically every object around you has INERTIA, moving or not. A way for me to describe INERTIA is if you were in a moving car with your seat-belt on and the car suddenly stopped, you would move slightly forward. You do this because you HAVE INERTIA, which has effectively being given by the moving car. The seat-belt saves you and halts your momentum. FRICTION generally halts the movement of everyday things I.E it stops the car mentioned (BRAKES).

2. It's much easier to make something lightweight move than something super-heavy. Sound obvious?? Think of a bicycle and a lorry or a car. "Acceleration" means speeding up and that's what happens if you push something in a direction or drive/ride a vehicle. The harder you push or the more you put your foot down, the greater the acceleration. The less weight (bicycle) will accelerate quicker and easier. In physics, acceleration means ANY CHANGE from being still to moving, whether your getting up of the settee or running 100m. So if you are driving a car and you brake to slow down, the force of FRICTION gives you NEGATIVE ACCELERATION (you decelerate).

3. When a rocket pushes burninggas out of its engine, the gas pushes back on the rocket and lifts it into space. Forces can also be labelled as "actions" and always work in pairs. If one object pushes another then that object pushes back with the same force - the forces are equal. The effects may not be however as if you were to throw a tennis ball, the ball pushes back on your hand but the ball can travel a good distance. If you push down on the ground with your feet and the ground pushes back and flings you up into the air - you jump. The force from your feet also moves Earth! but not enough to notice!!