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Forces and Motion

How to Calculate Acceleration.

How is the Acceleration of an Object Calculated?

Acceleration = Change in Velocity ÷ Time.

a = (v-u) ÷ t

where a = acceleration
v = final velocity (the one it ended up with)
u = initial velocity (the one it started with)
t = time

This equation can be rearranged.

Example 1. If a car changes from 10 m/s to 30 m/s in 8 seconds,
what is its acceleration?

v = 30
u = 10
t = 8

a = (30 - 10) ÷ 8
= 20 ÷ 8
= 2·5
m/s2

Example 2. If a bicycle moving at 15 m/s takes 10 seconds to stop,
what is its acceleration?

In this example,
the final velocity is zero because the bicycle has stopped.

v = 0
u = 15
t = 10

a = (0 - 15) ÷ 10
= -15 ÷ 10
= -1·5 m/s2

The acceleration is negative because the bicycle has slowed down.

What is Constant Acceleration?

Acceleration is the rate of change of an objects velocity.
The object is said to have constant acceleration if
it gets faster (or slower, or its direction changes) at the same rate.

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