(L5) Mechanics 1 - Kinematics Flashcards
What is speed?
Rate of change of position of that object at a given time.
What is average speed?
v,av= total distance travelled / total time it takes
What is instantaneous speed?
Speed of an object at a particular time?
Avergae speed gets closer to instantaneous speed as we reduce Δx and Δt. Since there’d be only 1 moment to take the speed at.
What is linear acceleration?
Uniform or Linear acceleration means the change in the speed is the same every second. e.g constant 2m/s^-1 increase.
What is acceleration? (scalar)
Rate of the change of speed.
What is the average speed formula?
v,av = v,f+v,i / 2
or v,av = total distance/total time
distance equation for object that starts at rest?
distance equation for object that has uniform acceleration, and isn’t at rest?
What is displacement?
Name for vector which has direction and distance (magnitude)
What is velocity?
Rate of change of displacement
What is acceleration (vector)
Rate of change of velocity
How to add velocities at different angles
Trigonometry
What is gravity? What is gravity equation?
All objects falling to earth accelerate at the same speed of 10m/s or 9.81m/s.
∆v = g∆t
‘If you drop a ball from a plane, what’s distance it falls?’
What equation should be used?
‘Throw a cricket ball straight up at 30m/s, how high will it go?’
What equation should be used?
∆v = g∆t –> ∆t = ∆v/g
find time as 3s since g=10m/s
then use average speed
then ∆x = v,av*t =45m
How long will the ball take to reach the ground again? from 45m high
What equation should be used?
hence, same 3s it took to go up.. to come down.
downward velocity at ground:
∆v = g∆t = 30m/s
hence, same 30m/s it was thrown up at.
