# Further Physics

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• Created by: phoebe_98
• Created on: 11-04-15 17:13
WHY DOES AN OBJECT TOPPLE OVER?
A large enough tilt will cause the line of action of the object to fall outside of the objects base causing it to fall over
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HOW CAN THE STABILITY OF AN OBJECT BE INCREASED?
Increasing the width of its base and lowering its centre of mass.
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GIVE AN EXAMPLE OF A HYDRAULIC SYSTEM AND HOW IT WORKS
Car brakes – a force is applied to a pedal increasing the pressure of oil in a cylinder and pipes. This applies a force on the brake pedals
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WHAT IS A FORCE MULTIPLIER?
A small force is applied to a lever a long way from the pivot. A much larger force is exerted by the lever closer to the pivot as the 2 moments have to be the same
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WHAT DOES THE CENTRIPETAL FORCE DO AND GIVE AN EXAMPLE?
It makes an object move in a circular path and has to act towards the centre of the circle as the object is always accelerating e.g. planet orbiting the sun, electron in atom, washing machine etc
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HOW CAN THE CENTRIPETAL FORCE BE INCREASED?
Increase the mass of the object, increase the speed and decrease the radius of the circular path.
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NAME SOME PRECAUTIONS THAT SHOULD BE TAKEN IF SOMEONE IS WORKING WITH XRAYS
Stand behind lead/concrete shielding, leave the room, wear a monitoring badge and limit the amount of time spent working with x-rays
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WHAT IS TOTAL INTERNAL REFLECTION AND WHEN DOES IT OCCUR?
It is where all light rays reflect off the boundary without losing intensity. This only happens when the angle of incidence is greater than the critical angle
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WHAT IS THE DIFFERENCE BETWEEN XRAYS AND ULTRASOUND?
X-rays are high energy waves that have a very short wavelength. They are very penetrating and ionising. Ultrasound has a frequency above human hearing range and are non-ionising.
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DESCRIBE TWO MEDICAL USES OF ULTRASOUND
Prenatal scanning - produce an image of fetus as they are much safer than x-rays (non-ionising). Kidney stones - high intensity beam breaks the stones into smaller pieces so they flush out with urine
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HOW DOES THE EYE CONTROL HOW MUCH LIGHT ENTERS IT?
Cells on the surface of the retina can be damaged if they absorb too much light. Therefore, pupil gets smaller in bright light to prevent this happening which is altered by the muscles in the iris.
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HOW CAN THE POWER OF A LENSE BE INCREASED?
The focal length has to be reduced which can be done by either increasing the refractive index (how fast light travels in a material) or increasing the curvature of the lens
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HOW ARE X-RAY IMAGES FORMED?
Photographic film is used to diagnos bone fractures or dental problems. X-rays are detected which is then shown as an image by CCD's
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WHY ARE SOME PEOPLE SHORT SIGHTED?
The image is focused in front of the retina so distant objects are blurry. This can occure if the eyeball is too large or lense cant be made thin enough. It can be sorted by adding a diverging lens in front.
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HOW ARE OPTICAL FIBRES USED?
They can carry pulses of infrared over long distances for telephone and internet communitcations. They allow photos to be taken deep inside the body. A bundle of fibres carry light into the body and a lens collects reflected light forming an image
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WHAT DOES THE EFFECT OF THE TURNING FORCE DEPEND ON?
Size and direction of force as well as how far from the pivot it acts
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## Other cards in this set

### Card 2

#### Front

HOW CAN THE STABILITY OF AN OBJECT BE INCREASED?

#### Back

Increasing the width of its base and lowering its centre of mass.

### Card 3

#### Front

GIVE AN EXAMPLE OF A HYDRAULIC SYSTEM AND HOW IT WORKS

### Card 4

#### Front

WHAT IS A FORCE MULTIPLIER?

### Card 5

#### Front

WHAT DOES THE CENTRIPETAL FORCE DO AND GIVE AN EXAMPLE?