Unit 1 - Our Dynamic Universe (Part 1) Flashcards
what is a vector quantity?
magnitude and direction
what is a scalar quantity?
no direction just size
define velocity
the rate of change of displacement (displacement covered in a certain time)
define acceleration
the rate of change of velocity (change of velocity in a certain time)
what experiments do you use to find velocity and acceleration?
Measure velocity using one light gate, measure acceleration using two light gates
Acceleration is …. proportional to force
Acceleration directly proportional to force - acceleration of any object in same direction as unbalanced force acting on it
REVISE GRAPH OF MOTION - JUST FOR 5 MINUTES!
DONT SKIP YOU KNOW YOU DONT UNDERSTAND IT THAT IS WHY YOU HAVENT DONE ANY CUE CARDS FOR IT!!!!!
define projectile motion
object projected horizontally or at an angle
what is the projectile motion made up of?
constant horizontal velocity v=s/t and constant vertical acceleration (use SUVAT)
define balanced forces
Forces equal in size, opposite in direction
state newton’s first law of motion
an object will remain at rest or will remain at constant velocity unless acted upon by an unbalanced force
what is friction
a resistive force that increases with velocity and always acts against the against the direction of motion
define unbalanced forces
opposite in direction, unequal in size - causes acceleration
what is weight?
a force caused by the presence of a mass in a gravitational field - measured in newtons (N)
define Gravitational field strength
the force per unit mass
state newtons second law of motion
the acceleration of an object varies directly with the unbalanced force and inversely with mass - F=ma - where F is equal to the unbalanced force which is calculated first.
in a lift when will the the reading on some scales be heavier?
accelerating upwards, decelerating downwards
in a lift when will the the reading on some scales be normal?
at rest or at constant speed
in a lift when will the the reading on some scales be lighter?
decelerating upwards, accelerating downwards
define power
the rate at which energy is transferred, measured in watts (w)
what is 1 watt equal to?
1 joule per second
state the law of conservation of energy
energy is never created nor destroyed - changed from one form into another
state newtons third law of motion
if A exerts a force on B, then B exerts an equal but opposite force on A - forces exist in pairs that are equal in size but opposite in direction both occuring at the same time
what is terminal velocity?
constant speed reached when air resistance balances weight
what is momentum?
mxv - Greater mass, greater momentum - large amount of force to get moving and bring to rest
what is the Law of conservation of linear motion/momentum?
total momentum before an interaction is equal to the total momentum after an interaction, in the absence of external forces
what is the difference between and elastic and inelastic collision?
Energy conserved, Ek before = Ek after - elastic collision
energy not conserved = inelastic collision
what is impulse (ft)?
change in momentum
how to you find impulse from a graph?
area under force-time graph
