Motion

What is the definition of speed?

The rate of change of distance

What is the definition of velocity?

The rate of change of displacement

What is the gradient of a distance-time graph?

Speed

What is the gradient of a displacement-time graph?

Velocity

What is the definition of acceleration?

The rate of change of velocity

What is the definition of instantaneous velocity?

The velocity at a particular point in time

What is the tangent to a displacement-time graph?

Instantaneous velocity

What is the gradient of a velocity-time graph?

Acceleration

What is the gradient of the tangent in a velocity-time graph?

Instantaneous acceleration

What is the area under a velocity-time graph?

Displacement

What are suvat equations valid for?

Constant acceleration

When is acceleration positive?

When it is in the direction of motion

When is acceleration negative?

When it is opposite the direction of motion

What is the equation for stopping distance?

Stopping distance = thinking distance + braking distance

What is the definition of thinking distance?

The distance travelled by the vehicle from the moment the driver sees reason to stop to the moment they apply the brakes

What is the definition of braking distance?

The distance travelled from the moment the driver applies the brakes to the moment the car stops

What is the equation for thinking distance?

Thinking distance = initial speed x reaction time

Which factors affect thinking distance?

Condition of the driver, alcohol, drugs, tiredness. These increase reaction time. As reaction time is directly proportional to thinking distance, thinking distance increases.

Which factors affect the braking distance?

Conditions of the car or the road. For example: conditions of tires, mass of vehicle, initial speed of vehicle, conditions of brakes, if road is wet or slippery

What happens if the velocity of a car doubles?

The kinetic energy increases by 4

If we double the speed of a car, what happens to the stopping distance?

It increases by 4