P2.1: Motion Flashcards
What is a scalar?
A scalar is a quantity which has size/magnitude only
What is a vector?
A vector is a quantity which has size and direction
Vector quantity may be represented by
Arrow
Name scalar quantities
Mass, speed, time, power, volume, energy and distance
Name vector quantities
Displacement, velocity, force, pressure, weight
How is velocity different to speed?
Speed but with a direction
Steeper the gradient
Faster the speed
Negative gradient indicates
The object is returning back to the start point
A horizontal line indicates
The object is stationary
If the gradient is not a straight line it indicates
It show the velocity is changing and the object is accelerating or decelerating
SDT Formula
Speed = Distance / Time
Speed is measured in
metres per second (m/s)
Distance is measured in
metres (m)
A velocity-time graph tells us
The velocity of an object over time
Time is measured in
seconds (s)
Calculating acceleration
Acceleration = change in velocity / time
Acceleration
metres per second squared (m/s^2)
A distance-time tells us
The distance an object moves over time
Change in velocity
metres per second (m/s)
During circular motion the speed remains
constant
Centripetal force
The force is always acting towards the centre of the circle
Displacement
metres (m)
However the velocity is changing
as the direction is changing
Changing velocity means
there must be acceleration
Initial velocity
metres per second (m/s)
If there is acceleration
there must be a force
SUVAT
S - displacement
U - initial velocity
V - final velocity
A - acceleration
T - time
Final velocity
metres per second (m/s)
SUVAT Equation
s = ut + 1/2at^2
What is acceleration?
The rate of change of velocity
