Topic 2 Mechanics Flashcards
scalars
no direction only size
- mass
- energy
- temperature
- distance
- power
- speed
- time
vectors
both direction and size
- pressure
- force
- acceleration
- magnetic/electric/gravitational field strength
- displacement
- momentum
- velocity
distance definition
how far you have travelled (m)
displacement definition
the distance revelled in a particular direction (m)
speed definiiton
the rate of change of distance (distance/t)
velocity definition
the rate of change of displacement (displacement/t)
instantaneous speed definition
the rate of change of distance at one particular time (ms^-1)
average speed definition
the speed over a period of time (ms^-1)
acceleration definition
rate of change of velocity (v/t) ms^-2
when should you use equations of motion eg. v=u+at
if an object is accelerating at a constant rate ie. undergoing uniform acceleration
gradient of displacement-time graph represents
velocity
gradient of velocity-time graph represents
acceleration
area below line of velocity-time graph represents
displacement
area below line of acceleration-time graph represents
change in velocity (*still speeding up but the increase of velocity is getting less)
area below line of acceleration-time graph represents
change in velocity (*still speeding up but the increase of velocity is getting less)
area above x-axis of displacement graph represents
displacement in a positive direction, eg to the right of the origin
area below x-axis of displacement graph represents
displacement in a negative direction, eg. to the left of the origin
area above x-axis of velocity graph represents
motion in a positive direction (regardless of position)
area below x-axis of velocity graph represents
motion in a negative direction
area above x-axis of acceleration graph represents
acceleration in a positive direction (shows the direction of the net force)
area below x-axis of velocity graph represents
acceleration in a negative direction
relative velocity definition
the apparent or relative velocity of an object depends on the situation of the observer (called their frame of reference)
projectile motion definition
a projectile is an object moving through the air under the influence of only one force - gravity
why does the trajectory (path) of a projectile motion follows a parabola?
- VERTICAL component of velocity is constantly CHANGING (due to the force of gravity)
- HORIZONTAL component of the velocity is CONSTANT (assuming no air resistance)
- at the top vertical velocity = 0