Pendulums

Starter• What is the equation that links time period, T, and

frequency, f?T = 1 /f or f = 1 / T

• What affects the frequency of a simple pendulum? Mass, length, how much it swings?

Just length!• Why did grandfather clocks have pendulums? They kept constant time, independent

of amplitude or mass• What would happen to a pendulum on the moon?

Pendulums

Identify the factors that affect the frequency of

a pendulum

Investigate the relationship

between length and time period

Rearrange the pendulum

equation to analyse their

motion

Main

• Using the worksheet to help you, set up the equipment safely and record your measurements in an appropriate manner.

• Collect the second sheet to guide you through the rest of this investigation.

Warning – take care that the retort stand is set up safely and will not topple over.

• ‘T2‘ is proportional to ‘l’ because

• This means that the only two factors that affect the time period of a pendulum are the length and the strength of gravity.

• The mass and how far is swings back and forth do not affect it since they are not in the equation.

T2

l

Pendulums

Identify the factors that affect the frequency of

a pendulum

Investigate the relationship

between length and time period

Rearrange the pendulum

equation to analyse their

motion

Plenary - 1

• As an astronaut who has just landed on another planet, how could you measure the strength of gravity using common items found on a space craft?

g = l x 4π2 / T2

Plenary - 2

• You own a fairground, and want to build a giant swing that is 10m high. To ensure it is safe enough for the thrill seekers you need to know the frequency.

• How would you calculate this and what would it be?

0.16 Hz