Friday, May 02, 2008

memorable kiss #1.

Sawyer & Kate, Lost.

Photobucket

11 comments:

Cal said...

Don't that be Sawyer?

Emma said...

LOL yes!!! *corrects it*

I honestly don't know what came over me there. Don't tell anyone.

Cal said...

It'll be our little secret!

anahita said...

looool, never seen lost before, but he is literally sticking his tongue in her mouth

edward said...

but he is literally sticking


http://yourfreemoviedownloads.com

Linds said...

I love this kiss.

How's Economics revision going Emma?

Emma said...

Lolz... how would "not well" sound? :P

Linds said...

Ditto. Ditto.

This is what I've got so far:

(a) distinguish between tariffs and quotas.
Tariffs and quotas both serve the purpose of controlling the number of foreign products that can enter the domestic market. A tariff is a tax on imported goods. Tariffs can be used by governments to raise revenue to finance expenditure. However, they are most often used in a deliberate attempt to restrict imports.
A quota is a physical limit on the quantity of a good imported. Imposing a limit on the quantity of goods imported into a country will increase the share of the market available for domestic producers. However, it will also raise price of the protected product.
(b) Assess the basis for trade liberalisation as promoted by the World Trade Organisation.

Studies such as those from which the following facts are culled demonstrate that current trade liberalization rules and policies have led to increased poverty and inequality, and have eroded democratic principles, with a disporportionately large negative effect on the poorest countries. It is such studies that have provided the impetus for restructuring the WTO as the TRO.

Emma said...

Hehe spam my blog will you? Everyone else does.

Linds said...

Don't mind if I do.

Force on a wire in a magnetic field

- If a wire carrying a current is placed at right angels to a magnetic field there is a force on the wire that may make it move.
- A bigger current or a bigger magnetic field will increase the size of the force on the wire.
- Reversing the current or the magnetic field will reverse the direction of the force. Fleming’s left-hand rule tells you the direction of the force.
- A loudspeaker makes use of this effect.

The force on a wire in a magnetic field
A straight wire connected to a power supply is placed between the poles of a powerful magnet. When the power supply is switched on the wire moves sharply = kicks in the direction at right angels to both the current and the magnetic field. This means that there is an unbalanced force on the wire.

Why does this happen?
The magnetic fields due to the current in the wire and the permanent magnet interact.
On one side of the wire the two magnetic fields act in the same direction, giving an extra strong field. On the other side of the wire the magnetic fields act in opposite directions, so that they partially cancel, giving a weak field. This means that there is an unbalanced force on the wire, so it moves sharply out of the magnetic field in the direction shown.

Making the force bigger
The size of the force can be increased by:
- Increasing the current in the wire.
- Using a more powerful magnet.

Changing the direction of the force
The direction of the force can be reversed by:
- Reversing the current direction in the wire.
- Reversing the poles of the permanent magnet.

Fleming’s left hand rule
- The first finger points to the direction of the magnetic field.
- The second finger points in the direction of the current.
- The thumb points in the direction of the thrust (force).

If the wire were not at right angels to the magnetic field, the size of the force would be reduced. It would be zero if the wire were parallel to the magnetic field.

Loudspeaker
- The input current to a loudspeaker is an alternating current of the same frequency as the original sound wave.
- The size of the current depends on the loudness of the original sound.
- The permanent magnets are circular so the coil lies in the uniform magnetic field between the N and S poles.
- When there is a current in the coil, there is a force on the coil.
- As the current direction alternates, the direction of the force alternates.
- This makes the coil, and in turn the paper cone and surrounding air, vibrate at the same frequency as the original sound wave.

- The alternating current that represents a sound wave flows through the coil.
- As the current carrying coil is inside a magnetic field a force is produced, which makes the coil move.
- This pulls the paper cone in the same direction. As the current changes direction, the force produced changes direction. This makes the paper cone move the opposite way. The backward and forward motion of the cone produces a sound wave in the air.
The higher the frequency of the electrical signal, the higher the frequency of the sound wave produced, so making a higher pitched noise. The greater the amplitude of the electrical signal, the greater the force produced, so the further the cone will move, making a louder noise.

Relays


- When the switch (S1) is closed, the current flows into the relay and magnetises the iron core.
- The magnetised iron core attracts the iron armature, which in turn presses the two contacts together, completing the output circuit.
- The output circuit is now complete and current flows to light the bulb.
- When S1 is opened, the current of the input circuit is stopped. This demagnetises the relay, which the contacts, stopping the current in the output circuit.

This type of relay circuit is used in the ignition of a car.

Electric Motors
- When a coil of wire is placed in a magnetic field, equal and opposite forces act on the sides of it, making it spin.
- A split-right commutator is needed to produce continuous rotation.
- Motors can be made more powerful by increasing the current in the coil, the number of turns on the coil or the strength of the magnetic field.

Forces on a coil in a magnetic field
A coil carrying a current is placed between the poles of a magnet. There is a force on each side of the coil, but in opposite directions, so the coil turns.
The coil can only rotate through 90 degrees. A motor needs to rotate through a full circle.

The split ring commutator
The split ring commutator reverses the current in the coil each time the coil passes the vertical. This keeps the forces in the coil in the same direction so that it keeps turning.

Emma said...

Grr Fucking Physics! I can't do it! I revise it but none of it goes in!