Accelerated Motion Flashcards
Acceleration definition
the rate of change of velocity of an object, unit ms^-2
Acceleration formula
a = ∆v / ∆t
a = (v - u) / t
Deducing acceleration
the gradient of a velocity-time graph shows the acceleration
Velocity-time graphs,
straight line
slope
no slope (flat line)
downwards slope (negative)
changing slope (curve)
constant acceleration
the greater the slope the greater the acceleration
a = 0 hence velocity is constant
negative slope shows deceleration
acceleration is changing
Deducing displacement
The displacement of a moving body can be found by the area under a velocity-time graph
Constant acceleration definition
When the change in velocity of an object is the same in the same period, can be called uniform acceleration
Equations of motion,
restrictions
given formulas
formulas to memorise
can only be used for
- motion in a straight line
- an object with constant acceleration
v = u + at {derived from a = (v-u) / t}
s = [(v+u)/2] x t {derived from (u + v)/2 }
s = ut + 1/2at^2 {derived from equation 1 and 2}
v^2 = u^2 + 2as {derived from equation 1 and 2}
Instantaneous acceleration from a v-t graph
Draw a tangent to the curve at this point and determine the gradient of the tangent
Non-uniform acceleration definition
when the velocity of an object changes by different amounts in the same period of time
Acceleration caused by gravity
9.81m^-1
Free fall definition
when an object accelerates due to gravity in the absence of any other forces such as air resistance
Component definition
the effect of a vector along a particular direction
Velocity and θ equations
going away from the angle to get to the direction is sin
going through the angle to get to the direction is cos
Projectile motion
A projectile can be split into 2 to have either u or v as zero
with air resistance negligible Vh has constant velocity meaning
v = d / t can be used, this also means Vv should have constant acceleration
remember to factor in direction (positive and negatives)
