the rate of change in distance over a completed journey
Instantaneous speed is the speed of the car over a very short peroid of time.
Define average velocity
the rate of change in displacement over a completed journey
Define acceleration
the rate of change of velocity
Acceleration is the gradient of a velocity-time graph, displacement is the area under it.
Thinking distance is the distance travelled between the moment when you first see a reason to stop to the moment when you use the break. It is the product of speed and reaction time
Braking distance is the distance travelled from the time the break is applied until the vehicle stops
Define acceleration of free fall
The rate of change of velocity of an object falling in a gravitational field
The value of gravity can be investigated using an electromagnet and trapdoor, light gates and taking pictures as the ball falls
