Topic 2: Mechanics Flashcards
What is a scalar?
A quantity that only has a magnitude
Eg. distance, mass, temperature, time, speed, energy, power
What is a vector?
A quantity with both mass and direction
Eg. displacement, pressure, force, field strength, acceleration, velocity, momentum
How do we write vectors?
If working in one dimension, consider one direction to be negative and the other to be positive
If working in two dimensions then we draw arrows to represent the quantities
What is distance?
How far you have travelled (m)
What is displacement?
The distance travelled in a particular direction (m)
What is speed?
The rate of change of distance (ms^{-1})
What is velocity?
The rate of change of displacement (ms^{-1})
What is instantaneous speed?
The rate of change of distance at one particular time
What is average speed?
The speed over a period of time
What is acceleration?
The rate of change of velocity (ms^{-2})
How do we determine the direction of the acceleration?
It will be in the same direction as the net force which is causing the direction
What is acceleration due to gravity on Earth?
9.81 ms^{-2} downwards
When can we use the equations of motion?
If an object is accelerating at a constant rate (ie. undergoing uniform acceleration).
What are the 4 equations of motion?
v = u + at
v^2 = u^2 + 2as
s = ut + 1/2 at^2
s=(v+u)t/2
What do the letters in the equations of motion stand for?
displacement - s (m)
time - t (s)
initial velocity - u (ms^{-1})
final velocity - v (ms^{-1})
acceleration - a (ms^{-2})
