Key learning 1: energy conservation in a system can be explained by describing energy transfers and transformations. 

Key learning 2: the motion of objects can be described and predicted using the laws of physics

Acceleration is a vector quantity defined as the rate at which an object changes its velocity. An object is accelerating if it is changing its velocity. 

If the velocity is changing by a constant amount every second it is called constant acceleration. 

Velocity is a vector quantity defined as the rate at which the position of an object changes. 

Traveling at a constant velocity means you're traveling at the same speed, in the same direction continuously. Having a constant velocity means you have zero acceleration. 

Image retrieved from https://www.youtube.com/watch?v=J6EMIHTr3uE on May 29, 2019

Scalar versus Vector Quantities

Scalar quantities are described by a magnitude (numerical value) alone

Vector quantities are described by both magnitude and direction

Distance versus Displacement

Distance: the measurement of how far apart objects are [scalar quantity]

Displacement: a measurement of the change in position of a moving body. A straight line connecting the start and the end points is specified in terms of length and direction. [vector quantity]

Speed versus Velocity

Speed: the rate of change of distance [scalar quantity]

Velocity: rate at which the position changes [vector quantity]

Formula for Calculating Velocity

There are 7 base SI units:

• Length - metre (m)
• Time - second (s)
• Amount of substance - mole (mole)
• Electric current - ampere (A)
• Temperature - kelvin (K)
• Luminous intensity - candela (cd)
• Mass - kilogram (kg)

Some common mathematical prefixes to be familiar with are:

• nano (n) - 10^-9
• micro (µ) - 10^-6
• milli (m) - 10^-3
• kilo (k) - 10^3
• mega (M) - 10^6
• giga (G) - 10^9

Scientific notation is a way of writing very large or very small numbers. To write in scientific notation, a number between 1-10 is multiplied by a power of 10. For example: 650 000 000 can be written as 6.5 X 10^8 and 0.0000076 can be written as 7.6 X 10^-6. The power is simply an indicator of how many places you have moved the decimal point either to the left (+) or the right (-).