Acceleration

Acceleration is how quickly you’re speeding up

• Acceleration is definitely not the same as velocity or speed
• Acceleration is the change in velocity in a certain amount of time
• You can find the average acceleration of an object using:

Acceleration=Change in velocity / time

• Deceleration is just negative acceleration

You need to be able to estimate acceleration

You might have to estimate the acceleration of an object. To do this, you need the typical speeds from the previous page:

• First, give a sensible speed for the car to be travelling at
• Next, estimate how long it would take the car to stop
• Put these numbers into the acceleration equation
• The question asked for the deceleration so you can lose the minus sign

Uniform acceleration means a constant acceleration

• Constant acceleration is sometimes called uniform acceleration
• Acceleration due to gravity is uniform for objects in free fall. It’s roughly equal to 9.8m/s2 near the Earth’s surface and has the same value as gravitational field strength
• You can use this equation for uniform acceleration
• v2-u2=2as, Final velocity-initial velocity = 2 acceleration x distance