Laws of Motion - Linear Motion

Hi,

I thought I'd blog some study/revision I'm currently doing for an exam. This won't necessarily be a comprehensive explanation of the topic, rather just the relevant formulas and notes that I'd personally create for myself when studying for an exam.

This entry is on linear motion and uses the "Engineering Mechanics" book by "Val Ivanoff".

Linear displacement , a vector quantity (distance and magnitude), is described as the position change of an object from one place to another along its path. The symbol for displacement is "S" and the SI base unit is m (metres).

Linear Velocity is the change in position of an object which occurs in time or the time it takes to change from one position to another. The symbol for linear velocity is "v" and SI base unit is in m/s (metres/second). This is most commonly used when referring to the speed of a car. For example, "I'm currently travelling 60km/h sounds better than 16.7m/s". To convert m/s to km/h the equation is:

v * (3600/1000)

or the other way

v = km/h / (3600/1000)

Linear Acceleration is used if velocity is not constant but rather increases gradually at a uniform rate. The symbol for this is "a" and the SI base unit is m/s^2. The relevant formulas are:

a = v - v0 / t

or 

v = v0 + at

Where:

• a = Acceleration (m/s^2)
• v0 = Initial Velocity (m/s)
• v = Final Velocity (m/s)
• t = Time (s)

There are a few handy formulas in relation to linear motion that can be used when you're missing a variable in an equation.

S = t * v(av)

or 

S = t * (v0 + v / 2)

v(av) or velocity average is simply v0 + v / 2

The above equation can be used when acceleration isn't known.

  v = vo + at

The above equation can be used when displacement isn't known.

S = vo t + at^2 / 2

The above equation can be used when final velocity isn't known.

2aS = v^2 - v0 ^2

The above equation can be used when time isn't known.

TO BE CONTINUED...