Unit 2: Mechanics

Motion

displacement – distance from point in direction

$v = \frac{\Delta s}{\Delta t}$

average speed (with constant acceleration!):

$ \begin{aligned} s &= \frac{1}{2} (v + u)t \\\\ v_{avg} &= \frac{1}{2}(v+u) \end{aligned} $

$u$ – init. velocity

$v$ – final velocity

acceleration – rate of change of $v$ with time

$a = \frac{\Delta v}{\Delta t} = \frac{v-u}{t}$

instantaneous velocity – $v$ at a particular time

instantaneous acceleration – $a$ at a particular time

$ \begin{aligned} v &= u + at \\ s &= \frac{(v+u)t}{2} \end{aligned} $

horizontal component is constant if no air resistance.

components can be used separately!

If no air resistance and $g = 9.81 ms^{-2}$:

$\overbrace{mgh}^{\text{grav. pot. E}} = \overbrace{\frac{1}{2}mv^{2}}^{\text{kinetic E}}$
$v = \sqrt{2gh}$

vertical component: find time before max h, time before ground

horizontal component: find max horiz. distance

unit N (Newton)

Types of force: