bEquations of motion/b
(\text{average velocity} = \dfrac{\text{displacement}}{\text{time}})
(\text{acceleration} = \dfrac{\text{final velocity}-\text{initial velocity}}{\text{time}})
For the movement of an object in a straight line with constant acceleration, the following letters are used:
(s) for displacement
(u) for initial velocity
(v) for final velocity
(a) for acceleration
(t) for time
These are used for the so-called isuvat/i formulae:
(v = u + at)
(s = ut + \frac{1}{2}at2)
(s = \frac{1}{2}(u+v)t)
(v2 = u^2 + 2as)
(s = vt - \frac{1}{2}at2)
To use these formulae, write down the known variables from the question. The question will tell you at least 3 variables out of the 5. Identify the appropriate equation to use for solving the unknown variables.
bVertical motion under gravity/b
isuvat/i formulae can also be used to model vertical motion under gravity.
For a falling object, acceleration towards the Earth is constant (ignoring air resistance) and is equal to the gravitational constant (g) ((\approx 9.81ms-1)).
For an object being thrown upwards vertically, it will have a negative acceleration equal to (-g) (again ignoring air resistance).
[b]uFormulae for constant acceleration for motion in a straight line[/u]/b
(v = u + at)
(s = ut + \frac{1}{2}at2)
(s = \frac{1}{2}(u+v)t)
(v2 = u^2 + 2as)
(s = vt - \frac{1}{2}at2)