Slides in this set
Equal and opposite forces
· When two objects push or pull on each other the
exert equal and opposite forces
· resultant force is the single force that would have
the same effect on the object as all the other
· resultant force = mass x acceleration
· When resultant for is zero, it means that a stationary
object will stationary or move at constant speed.
· When a object is travelling at constant speed, the
frictional forces balance the driving force.
· Stopping = breaking + thinking…read more
Work and energy
· Work done = energy transferred
Work done = force x distance
· If two objects were to collide, the total momentum
before the collision is equal to the total momentum
afterwards aka conservation of momentum
Momentum = mass x velocity
· Momentum has size and direction like velocity.
· When a force acts on a moving object its momentum
force = change in momentum
time taken for change…read more
· If two insulating materials rub against each other,
electrons are rubbed off one material and deposited
on the other
· One material becomes negatively charged whereas
the other becomes positively charged due to the
gain/loss of electrons.
· Like charges repel and opposite charges attract, the
bigger the distance between the forces, the weaker the
When a charge flows through a conductor, there is a
current in it. Electric current is the rate of flow of
· The reason metals are good conductors of electricity
is because they have a sea of delocalised electrons
(they aren't attached to an atom).
· A conductor can only hold charge when it is isolated
from the ground otherwise electrons will flow to or
from the earth and discharge it. (Will be earthed)
· The bigger the charge the higher the pd (potential
difference) between object and earth.
· If pd becomes high enough a spark comes between
the object and earthed conductor…read more
· Used to paint cars allowing the paint droplets to
pass through a positively charged nozzle. So they
become positively charged and repel each other to
create a fine cloud of pain, so the paint is spread
over the car evenly.
Dangers of Electrostatics
· When filling you car with fuel, the pipe must be
earthed otherwise there would be a build up of
charge and eventually a spark would cause an