Motion and Static electricity

Equation for speed

Speed = distance/time

V = S/T

What js the difference between speed and velocity

Velocity is the speed of an object in a certain direction. Speed is simply how fast an object moves

What is displacement

Distance travelled in a particular direction

Velocity equation

Velocity = increase in displacement / time taken

What are the two factors in stopping distances

Braking distance - distance travelled whilst the brakes are applied

Thinking distance - distance travelled while reacting

What things affect reaction time

Age

Tiredness

Intoxication

What things affect braking distance

Road surface - grip/friction

Weather

Quality of brakes

Speed and mass of vehicle

Explain charging by friction

When objects are rubbed together , the force of friction can cause electrons to be transferred from one object to the other. This can cause objects to stick together as opposites attract. Such as a balloon sticking to a jumper

Explain charging by induction

A strong charge can attract or repel the electeons in another object. Even though electrons aren’t transferred to a new object, they are re-arranged causing a charge to build up

What is an electrostatic precipitator

A device used to remove pollutants when gas escapes out a chimney

Explain how an Electrostatic precipitator works. Long description

The hot gas rises up the chimney snd rubs against the negative metal grating.

The small molecules pass through easily. The large molecules rub against the grid more. Direction transfers electrons from. The metal grid to the gas molecules causing them to become negatively charged. As the gas rises further, the large negative gas molecules are attracted to the positive metal plates. The rest of the gas keeps rising and the negative molecules hit yhe plates and fall down the chimney as they lose their negative charge and energy.

Explain how photocopiers work

Light is shine on the paper where the ink needs to go. This causes electrons to escape the paper.

This leaves a pattern of positive charge.

The negatively charged is attracted to the positive parts on the paper. When the ink lands, the charge becomes neutral so there isn’t too much ink on one spot as the ink will no longer be attracted.

An even costing of ink is left where the light was shone

Explain insecticide spray

Negatively charged insecticide spray is spread evenly over the ground, causing the surface of the ground to be positive. This is charging by induction. The spray is attracted to the ground so it won’t blow away into rivers or lakes and harm wildlife.

Explain industrial spray painting

The spray paint is negatively charged so the droplets repel each other to give an even coat of paint. The surface is made positive so the paint drops are attracted to it.

Diagram for Electrostatic precipitator

Image for insecticide spray

Image for industrial spray painting

Equation for density

Density = mass / volume

Pressure equation

Pressure = force / area