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

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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

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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

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