# Stability

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• Created by: Cazza180
• Created on: 31-05-16 12:05

## Keeping an object stable

• Give it a low centre of mass

- The point where an objefct's mass may be thought to be concentrated

- Make the base heavier so the weight is thought to be concentrated at the bottom

• Have a wide base

- So it can topple further without falling as the line of action of weight doesn't go                              outside the base as soon

• Bolt or clamp down the base
•  An object topples over if the resultant momentabout its point of turning is not zero

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## Bus Stability

Busses have their stability tested so they are safe to travel on. They are tested to angles greater than it would expect to experience for

•                       When they go round bends and on hilly roads
•                       In case of bad weather conditions like a lot of wind
•                       When the bus has passengers, the centre of mass will be higher so it is less stable (especially if the bus is double decked, so passengers are at the top)

The bus will topple over if the ramp is tilted at too great an angle as

• The line of action of weight will go beyond the base of the bus
• So there's a resultant moment clockwise, causing the bus to topple clockwise

Buses have heavy engines so the engines are often placed at the bottom as well

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## Pendulums

The time for one pendulum swing depends on its... LENGTH

The shorter the length, the shorter the time period and vise versa

Bear in mind changing the amlpitude or mass of the pendulum will NOT ffect the time period

Time period = 1/frequency

time measured in seconds (s) and frequency measured in hertz (Hz)

A time period is the time taken for th pendulum to swing from one side to the other and back again

The time period for each swing is always the same on a given pendulum

Pendulum examples

• Playground swings
• Fairground rides
• Clocks
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