physics ep
define the term force
a push or a pull that acts on an object due to the interaction with another object
measured in newtons with newtonmeter
vector quantity
what is a vector quantity
any quantity that has both magnitude ( size) and direction
name 6 types of forces
1.Friction
2.Magnetic
3Air resistance
4Electrostatic
5Upthrust
6Magnetic
define air resistance
the force that opposes the movement of objects through air
Define friction
the force that opposes motion
define gravitational force
the force that causes by weight
define upthrust
the force experienced by objects when theyre placed into fluid
define electrostatic force
repulsive or attractive forces between particles that are caused by their electric charge
define unbalance force
the force apply to an object to one direction is greater than the force apply to the opposite direction
what is a brittle material
doesn't change shape but will break e.g. glass
what is a resilient material
it dont break easily
describe an elastic material
return to their orginal shape when the forces are removed
describe plastic materia
retain their new shape
describe the method on how to carry out an experiment to investigate the relationshp between friction and mass .
1) set up equipments as in diagram
2) pull the newtonmeter until mass is just about to move
3)remove 100g and repeat step 2
4)repeat until all mass removes then do it all again
5)plot a graph of force against mass
What is a current
a flow of electrical charge
-measured by an ampmeter
- I = P/V
-I = Q/T
define center of mass
the point where the point is said to act from
- usually at the center of an object
stopping distance
the sum of thinking distance and braking distance
define thinking distance
the distance travelled by a vehicle b4 the brakes are applied
- affected by speed of the vehicle + reaction time of the driver
define stopping distance
the distance travelled by a vehicle after the brakes are applied until the moment when the vehicle completely stops
-affected by mass + speed of the vehicle
-road surface
-quality of the brakes and tyres
terminal velocity meaning
when falling objects velocity remains constant ( they are still falling but not accelerating or decelerating )
resultant force
the combination of all the forces acting on an object
hooke's law equation
force = spring constant x extension
- k( newton ). cm or m
newton's 1st law
an object will remain at rest or constant velocity unless acted upon a net force
newton's second law ( force)
Net force = mass x acceleration
newton's third law
for every action , there is an equal and opposte reaction
equation for moment
moment = force x perpendicular distance
equation for average speed
avg speed = distance / time
charge equation
current x time
symbol Q
unit : coulomb
Q=IT
how does paint sparying work using electrostatic attraction
the spray paint gun is charged positively , causes every paint particle to become posetively charged - since all paint particles have the same charge , they repel each other and produce a fine mist of paint .
ionisation meaning
the process which atoms lose or gain electrons to become charged
give one hazaed caused byy electrostatic charges + how to prevent
can gives you electric shock , you need to earth the object
equation for energy
E = I x V x T
E = Q x V
E= P x T
measured in joules
difference between displacement and distance
displacement = vector
distance = scalar
define power
the rate at which energy is transferred
P=IV
watts
define voltage
volts - measure the energy trasferred per coulomb of charge
V= P/I
V= E/Q