🌀 INERTIA
p = m × v
Heavier = harder to stop!
F·t = Δp
Heavier = harder to stop!
F·t = Δp
A (10 kg): v=5 p=50 kg·m/s
Status: rolling!
B (5 kg): v=5 p=25 kg·m/s
Status: holds it!
Status: rolling!
B (5 kg): v=5 p=25 kg·m/s
Status: holds it!
Same speed, different masses. 10 kg boulder overwhelms the person; 5 kg boulder is stopped quickly. Momentum = inertia in motion!
💥 ELASTIC COLLISIONS
p = mv
v₁'=(m₁−m₂)/(m₁+m₂)·v
v₂'=2m₁/(m₁+m₂)·v
Total p conserved ✓
v₁'=(m₁−m₂)/(m₁+m₂)·v
v₂'=2m₁/(m₁+m₂)·v
Total p conserved ✓
SCENARIO
Ready
Real elastic physics! A doesn't always stop — mass ratio determines the outcome.
🔧 WORK & ENERGY
W = F·d·cosθ
Net Work = ΔKE
Net Work = ΔKE
Net Work = ΔKE. Friction reduces useful work!
⚡ KINETIC ENERGY
KE = ½mv²
Quadruples when v doubles!
Quadruples when v doubles!
KE grows with v²! Double speed = 4× energy.
🏔 POTENTIAL ENERGY
PE = mgh
PE → KE as ball falls
Total = constant
PE → KE as ball falls
Total = constant
Energy converts PE↔KE but total stays constant!
⚙ POWER
P = W/t = F×v
Same work, less time = More power
Same work, less time = More power
A: —
B: —
Winner: —
B: —
Winner: —
Faster = more powerful. Same work, different rate!
🪶 GALILEO'S EXPERIMENT
In air: Drag force acts on feather
F_drag = ½ρCdAv²
In vacuum: Only gravity acts
Both fall IDENTICALLY
h = ½g·t² v = g·t
F_drag = ½ρCdAv²
In vacuum: Only gravity acts
Both fall IDENTICALLY
h = ½g·t² v = g·t
ENVIRONMENT
Tower Height
55 m
Ball Mass
5 kg
Feather Mass
0.01 kg
g (gravity)
9.8 m/s²
⚽ Ball Time
—
🪶 Feather Time
—
⚽ Ball Speed
0 m/s
🪶 Feather Speed
0 m/s
Distance Fallen
Ball: 0.0m
Feather: 0.0m
Result
Press DROP to begin
Galileo's genius: All objects fall with the same acceleration in vacuum — regardless of mass! Air resistance separates them. In vacuum, even a 5 kg iron ball and a 10g feather hit the ground at exactly the same time.
💢 IMPULSE
J = F × Δt = Δp
Impulse = Change in momentum
Large F, short Δt
= Same impulse as
Small F, long Δt
Impulse = Change in momentum
Large F, short Δt
= Same impulse as
Small F, long Δt
SCENARIO
Force (F)
—
Contact Time (Δt)
—
Impulse J = F·Δt
—
Δp (change in p)
—
Before: v
—
After: v
—
Impulse = Δp ✓
Phase
Ready
Key insight: Airbags work by increasing Δt — same impulse (same Δp) spread over longer time = smaller peak force. That's why they save lives! J = F·Δt = Δp always.