# level 2 Physics

## 39 terms · Definitions and explanations for all external standards in level 2 Physics

### Scalar quantities...

have a size but no direction

### Vector quantities...

have a size and a direction

scalar

vector

### Newton's 1st law:

Every Object in a state of uniform motion (equilibrium) tends to remain in that state of motion unless an external force is applied to it

### Newton's 2nd law:

The relationship between an objects mass, its acceleration, and the applied force is F=ma. Acceleration and force are vector quantities. In this law the direction of the force vector and the acceleration vector is the same

### Newton's 3rd law:

For every action there is an equal and opposite reaction

### Projectile motion:

the motion of an object with one force on it, causing acceleration in only one direction (usually gravity)

### Conditions of Equilibrium:

net force is zero, net torque is zero

### Net force is the...

sum of force vectors

### Net torque is the...

sum of clockwise and anticlockwise torques

Newtons N

### Units of Velocity v

metres per second

Jules J

Newton metres Nm

Amps A

Teslas T

Hertz Hz

### Units of Momentum p

Kilogram metres per second

Watts W

### Voltage definition:

the energy transferred per coulomb of charge

### Current definition:

the rate of flow of charge

### Alternative Units of Current I

coulombs per second

coulombs c

### Units of Electric field strength E

Newtons per coulomb

### property of an elastic collision:

no kinetic energy is lost

### property of an inelastic collision:

some kinetic energy is lost to other energy forms

### principle of conservation of momentum:

momentum is conserved in a collision unless external forces act

### property of all waves:

transfer energy without transferring mass

### property of mechanical waves:

require a medium to travel through

### property of electromagnetic waves:

don't require a medium to travel through

### property of transverse waves:

displacement is perpendicular to the direction of travel

### property of longitudinal waves:

displacement is in the same direction as travel

### name of Dalton's model of the atom

'Billiard ball' model

### name of Thomson's model of the atom

'Plum pudding' model

'Nuclear' model

### name of Rutherford's famous experiment

alpha-particle scattering experiment

### components of Thomson's model of the atom

negative charges (detected in cathode rays) embedded in a matrix of positive charge

### components of Rutherford's model of the atom

negative electrons orbiting a very small, central, positive nucleus