G481 - Mechanics Flashcards
Unit of Length
metres
m
Unit of Time
seconds
s
Unit of Temperature
Kelvin
K
Unit of Electrical Current
Ampere
A
10^-12
Pico
10^-9
Nano
10^-6
Micro
10^-3
Milli
10^-2
Centi
10^3
Kilo
10^6
Mega
10^9
Giga
10^12
Tera
Scalar Quantity
Definition
A quantity that has magnitude but not direction
Vector Quantity
Definition
A quantity that has both direction and magnitude
Displacement
Definition
Distance moved in a certain direction from a point
m
Instantaneous Speed
Definition
Speed at a given moment in time
m/s
Average Speed
Definition
Total distance travelled / total time
m/s
Velocity
Definition
Rate of change of displacement
m/s
Acceleration
Definition
Rate of change of velocity
Velocity Time Graph
Grafient
Acceleration
Velocity Time Graph
Area
Displacement
Displacement Time Graph
Gradient
Velocity
Aristotle
Assumed without experimentation that heavier objects fall faster than lighter ones
Galileo
Dropped balls of different mass
Balls hit the ground at the same time
Acceleration of free fall is the same regardless of mass
Experiment to Find g
Measure the height the ball is dropped from
Time how long it takes for the ball to fall that distance
Use s=ut+0.5at² where u=0, s=height, t=time to fall
Force
Definition
An interaction between two objects involving a push it a pull
N
Newtons First Law
Every object continues in its state of rest or uniform motion in a straight line unless acted on by an external force
Newtons Second Law
F∝a
F=ma
Newtons Third Law
For every action there is an equal and opposite reaction
One Newton
Definition
Force required to give a mass of 1kg an acceleration of 1m/s²
Weight
Formula
F=ma
W=mg
Why can F=ma not be applied to objects travelling close to the speed of light?
Because as an object approaches the speed of light its mass increases
Weight
Definition
The gravitational force on a body