Forces and Motion Objectives: To review Speed Distance-Time Graphs Velocity-Time Graphs Acceleration Newton’s Laws Falling Objects Forces on vehicles

Speed Equation

Displacement – Time Graph Distance is how far you go. Displacement is how far you are from a particular place.

Displacement-Time and Velocity-Time Graphs Drawing graphs (gradient and area)

Acceleration Acceleration is the change in velocity over a given time. acceleration = Change in speed = (final speed – initial speed) Change in time (final time – initial time)

Forces Newton ’ s First Law. An object will remain stationary or go at a constant velocity unless there is a resultant force on it. This will make it change direction or change its speed.

Forces Newton ’ s Third Law Whenever you push something, it pushes back with the same type of force exactly the same amount. (Every force has an equal and opposite reaction force)

Forces Newton ’ s Second Law The acceleration of something is proportional to the amount of force on it and inversely proportional to its mass OR Force = mass x acceleration Pushing things Graphs

Falling Objects Drop stuff

Stopping Distance This is the distance moved by the vehicle between the driver seeing the obstacle and the vehicle stopping. The vehicle keeps moving at a steady speed whilst the driver reacts (thinking distance) The vehicle slows down whilst the brakes are applied (braking distance) Stopping = Thinking + Braking

Stopping Distance Total stopping distance is the area under the whole graph

Thinking Distance Factors that affect thinking distance are: driver tiredness; influence of alcohol or other drugs; more speed; distractions or lack of concentration.

Braking distance: Factors that affect braking distance are: road conditions – slippy, icy, wet; car conditions - bald tyres, poor brakes; more speed.