Twenty minutes or less.

5-minute version

Three threads. One sentence each.

• Workflow. Model -> Visualise -> Solve -> Assess. Picture first, equation second.
• SUVAT. Know 3 of $\{u,v,s,t,a\}$? Pick the equation that doesn’t contain the variable you don’t care about.
• Relative motion. ${\vec{v}}_{OG}={\vec{v}}_{OM}+{\vec{v}}_{MG}$ — switching frames can collapse a hard problem into one line.

Open the cheatsheet quiz, do 3 questions, close it. You’re prepped enough for the warm-up.

20-minute prep plan

Time	Action
0–5 min	Skim the cheatsheet — the SUVAT picker table and the sign-convention drill.
5–10 min	Rewrite one lecture example (Frisbee or Braking motorist) on paper, longhand, with the sketch first.
10–15 min	Take the cheatsheet quiz. Track which questions you slip on.
15–20 min	Read the matching section in the in-depth note for whatever you slipped on.

What to revise first

Most students slip on two specific things in this week:

1. Sign errors. $u,v,a,s$ are vectors. If you write $a=9.81$ for an upward-thrown rock with “up” positive, the rock won’t fall. Fix the axis on the sketch before you substitute.
2. Skipping the sketch. If your working has $u$ and $v$ in it but no picture, you don’t know which is which. The lecturer (slide 9): “this is where you should be spending your time.”

Key formulas

$v=u+ats=ut+\frac{1}{2}a{t}^2$

$v^2=u^2+2ass=\frac{1}{2}(u+v)t$

$g=9.81{\text{m/s}}^2\text{(magnitude; sign comes from your axis)}$

${\vec{v}}_{OG}={\vec{v}}_{OM}+{\vec{v}}_{MG}$

Likely workshop tasks

Task type	What the setup usually looks like
Single-stage SUVAT	Known 3 of $\{u,v,s,t,a\}$, find one of the remaining two
Free fall	Vertical motion, $
Multi-stage motion	Split at points where $a$ changes (e.g. mini-golf slopes, ball into water)
Relative motion	Two moving objects, “find the velocity relative to…” — pick the convenient frame

Mistakes to avoid

• Treating $g=9.81$ as automatically negative. The sign is set by your axis choice.
• Using SUVAT when $a$ isn’t constant. Split into stages first.
• Taking only the positive square root without checking physical context.
• Skipping unit conversion (km/h $\to$ m/s by dividing by $3.6$; cm $\to$ m by $/100$).
• Forgetting to assess — does the final number make sense as a speed, height, or time?

Mini self-test

Try these without notes. Eight minutes total.

1. A ball is dropped from $20\text{m}$. How fast is it moving when it hits the ground? How long did it take?
2. A car at $30\text{m/s}$ brakes at $5{\text{m/s}}^2$. How far does it travel before stopping?
3. Two trains approach head-on, one at $80\text{km/h}$ east and one at $50\text{km/h}$ west. What is the speed of the second train as measured from the first?

Answers:

Question	Answer
1	$v\approx 19.81\text{m/s}$ (downward); $t\approx 2.02\text{s}$
2	$s=90\text{m}$
3	$130\text{km/h}$ closing (i.e. $-130\text{km/h}$ in the first train’s east-positive frame)

Done checklist

• Read the cheatsheet’s SUVAT picker table.
• One lecture example copied longhand with sketch + sign convention.
• Cheatsheet quiz attempted.
• Mini self-test attempted.
• Pen, paper, calculator with km/h-m/s conversion comfortable.

That’s it. Close the laptop.

Source files used

• EGD102-Physics/Lecture2_CTP1.pdf
• EGD102-Physics/EGD102 - Lecture2 - Notes.pdf
• EGD102-Physics/Tutorial 2.pdf