Paper 2 phyciscs

What is a scalar quantity?

A quantity which has magnitude but no direction

What is a vector quantity?

A quantity which has magnitude and direction

Example of scalar quantity

(Stamped DT)

Speed

Time

A(filler)

Mass

Power

Energy

Distance

Density

Temperature

Examples of Vector quantity

VAMFWD

Velocity

Acceleration

Momentum

Force

Weight

Displacement

Terminal velocity

When an object falls through a liquid

When this happens, drag and speed will go from increasing, to staying the same and acceleration will go from decreasing to zero.

Inertial mass

How difficult it is to change the velocity of an object

What happens when two or more forces are applied to an object

Deformation (when an object changes shape.)

When elastic (changes back to original shape) work done is converted to elastic potential energy.

When inelastic (does not change back to original shape) work done is wasted as heat to the surroundings.

What does hookes law say about elasticity?

The force on the object is directly proportional to the extension

What is displacement?

The overall distance and direction an object moves from its starting position (vector version of distance)

What is velocity?

The speed of an object in a given direction

What is newtons 1st law?

If the forces on an object are balanced and there is no resultant force on it, the object is stationary/moving at a constant speed.

What is newton’s 2nd law

If the forces on an object are unbalanced and there is resultant force acting on it. The object accelerates.

What is newtons 3rd law?

When two objects interact, they exert force on each other which are equal and opposite.

What is inertia

An object’s tendency to keep doing what is is doing.

What are transverse waves

Waves that oscillate perpendicular to the direction of energy transfer.

e.g water waves/electromagnetic waves

What are longitudinal waves?

Oscillations are parallel to the direction of energy transfer.

e.g sound waves

What happens when a wave reaches a boundary between two materials?

Reflection

Absorption

Transmission

What can happen during transmission in a wave?

Refraction (when the wave enters a new medium)

• its speed changes

• therefore its direction also changes

electromagnetic waves

transverse waves that travel at 3 × 10^8 m/s in a vacuum

Spectrum for electromagnetic waves

Radio

Microwaves

Infrared

Visible

Ultraviolet

X rays

Gamma

*Top of list = high wavelength + low frequency, bottom is opposite

What are radio waves used for?

Wireless communication- created using transmitter.

Electrons oscillate + generate radio waves.

Radio waves match frequency to alternating current.

Waves travel long distance to receiver which absorb them + cause electrons to vibrate.

What are microwaves used for?

Satellite communication

Cooking

What is infrared waves used for?

Electric heaters

Infrared cameras

What is visible light used for?

Fibre optic communication - transfers large amounts of date over long distances

X - rays + gamma rays used for?

Medical imaging

cancer treatment (gamma only)

Which electromagnetic waves can be hazardous to humans?

Ultraviolet - skin age prematurely

X-rays - ionising radiation

Gamma waves - ionising radiation

What does the impact depend on?

Type of radiation

Dose

(Measured in sieverts)