Science Physics Flashcards
distance
- scalar quantity
- length of space covered between 2 points during an objects motion
displacement
- vector quantity
- objects overall change in position
- always measured from the 0 point in metres
speed
- scalar quantity
- how fast an object is moving
- rate which an object covers distance
velocity
- vector quantity
- rate at which an object changes its position
- does not tell anything about what happens to it between starting point and ending point
- if velocity changes, motion is accelerating.
acceleration
- vector quantity
- rate at which an object changes it velocity
- object is accelerating if the velocity is changing
- require an outside force such as gravity
- object with negative acceleration could be speeding up and object with positive acceleration could be slowing down
scalars
quantity described by a magnitude only
vectors
quantity described by both magnitude and direction
newton’s first law
- velocity of an object will remain constant unless acted upon by a net unbalanced force
example: ball will continue rolling but friction makes it slow down and eventually stop
newton’s second law
- net external force acting on a body is directly proportional to and in the same direction as the acceleration of the body
- force = mass x acceleration
example: skydiver jumps from a plane and accelerated until reaching highest velocity point but acceleration is 0. air resistance is equal to downward force of skydiver.
newton’s third law
- for every action, there is an opposite and equal reaction
example: presses on wall and wall pushes back for there is an equal and opposite force
inertia
- represented by newton’s first law
- object tends to stay at rest or continue motion unless acted by a force
- greater the mass, greater the inertia (harder to stop)
physics
- precisely define the most fundamental measurable quantities in the universe
- find relationships between fundamental measured quanities
instantaneous speed
-speed of an object at a particular moment in time
magnitudes of the instantaneous speed and velocity are always identical
instantaneous velocity
-velocity of an object at a particular moment in time
smaller displacement/ shorter time interval
position vs. time graphs
- horizontal line = no motion
- slope = velocity in x direction
- vertical axis = position of object
- slop represents velocity of the object
x2 - x1
———- = slope/velocity
t2 - t1
- if velocity/slope is constant, the acceleration is 0
velocity vs. time graphs
- vertical axis = velocity of object
- slope represents acceleration of the object
v2 - v2
———- = slope/acceleration
t2 - t1
- area = displacement
- area under graph represents displacement of the object
acceleration vs. time graphs
- vertical axis = acceleration of object
- slope represents quantity called ‘jerk’, rate of change of the acceleration
a2 - a1
———– = slope/ rate of change of acceleration
t2 - t1
- area under graph represents change in velocity
area = change in velocity
4V = v - u
if acceleration is high
velocity is changing rapidly
if acceleration is 0
velocity is exactly constant
ticker timer
- machine that makes a series of dots on paper as it moves through the machine
- each length of tape (6 dots) represents 0.1s
d (length of tape)
V= —————————
t (0.1s) - measures speed and/or acceleration
calculate resultant force
add forces acting on an object together (30N + 25N = 55N)
acceleration by newton’s equation
a = force/mass
momentum
- quantity of motion of a moving body.
momentum (p) = mass x velocity
weight
- force of gravity on an objects mass
weight (w) = mass x gravitational acceleration (g)
