By the end of this topic you should:

Objectives

Levers

Big question

• How many weights can I place on the ruler before it tips?

Hydraulics

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Pressure = Force Area

• Weight measured in Newton's N

• Area measured in meters squared M2

• Pressure measured Newton meters squared

N/ M2 or NM - 2

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If you push down one side 5 M the other will move?

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Centre of gravity

Center of gravity can be out side the object

• http://www.youtube.com/watch?v=QQh56geU0X8

Pendulum key words

• Amplitude (how far from vertical the string moves)

• Period ( time taken for one swing)• Frequency ( number of swings per secon)

Which falls faster heavy or light?

• http://www.bing.com/videos/search?q=happer+feather&view=detail&mid=4B4A1DFA822F65022B7B4B4A1DFA822F65022B7B&first=0&FORM=NVPFVR

Cirular motion

• http://www.bing.com/videos/search?q=wall+of+death+fair+ground&view=detail&mid=0A8553C1DD64230FA31E0A8553C1DD64230FA31E&first=0&FORM=NVPFVR

Centripetal force

• Is any force that acts at 90 degrees to objects motion (towards centre of circle) of object.

• With out which object flies off in straight line

• http://spacewar.oversigma.com/

Magnetic feilds

The earth acts as a magnet

The earth acts as a magnet

• Arrows on field are drawn north to south

• Where the lines are close together the field is strongest

• In electromagnets field can change direction by changing the current

• http://www.bing.com/videos/search?q=faraday+electric+motor&view=detail&mid=2F7A37DE404A15A0777A2F7A37DE404A15A0777A&first=0&FORM=NVPFVR

Make a stronger motor

• More coils of wire• More current• Stronger magnet

• (changing direction of current changes direction of spin)

• http://www.bing.com/videos/search?q=electric+motor&view=detail&mid=C357EF84B0840FC41766C357EF84B0840FC41766&first=0&FORM=NVPFVR

Practical problems

Step up transformer

• Always with respect to voltage

Less coils more coils

Step down transformer

• Always with respect to voltage

Less coils more coils

Stepping up

• 12 22

Stepping up

• 1:2 ratio voltage times 2

• 1:2 ratio voltage times 2• 1:3 ratio voltage times 3• 1:4 ratio voltage times 4• 1:5ratio voltage times 5

• Ratio = big number / small one