High Impact - The Forces #2

High Impact - Gravity, Air Resistance, Accelerate, Motion

Gravity -
What is Gravity? - Gravity is the force that is pulling things towards the centre of the Earth, and keeping us on it. Heres a story - While Sir Newton was sitting down under an apple tree, an apple fell down on him. He wondered, why did the apple fall downwards. Why didn't it go up, or any other direction? This thought led him to discover gravity, 
Why do we need gravity? - Without gravity, we wouldn't be pulled into Earth's core, instead, we would be flying off into space. For example, if you jump, you would come back right down onto the surface, because the gravity is pulling you into the Earth's core. 

Deep Thought : Looking at this drawing, if you think about it, down and up basically mean in and out. Into the core, and out to space. 

Air Resistance -
What is Air Resistance? - Air resistance is air moving against a moving object, and slowing it down. It is basically friction from air.
Why do we need air resistance? - It's beneficial in some activities, and dangerous in others. It forces us to use considerable energy in travel. Air resistance is needed in parachuting, skydiving, cars, and others. 

Acceleration - 
What is acceleration? - Acceleration is a force that makes objects increase in speed or rate. While objects move they gain acceleration, and acceleration makes them go faster. We use the single term acceleration to mean any change in velocity.
Why do we need acceleration? - So that things and/or people can go faster as they move forward. 

Motion -
What is motion? - Motion is when a person or object moves. 
Why do we need motion? - Because without motion, nothing would move! Everything will be immobile.

Newton's cradle is a device that demonstrates conservation of momentum and energy using a series of swinging spheres. Newton's cradle is named after Sir Isaac Newton