Physical: Asia: Breaking down the physics behind the 2.2-tonne cart, sinking wheels, and sand resistance in Quest 5

Episode 11 of Physical: Asia centers on Quest Five — Castle Conquest — where Korea, Mongolia, and Japan attempt to move a fully loaded 2.2-tonne supply wagon across deep sand, break a fortified gate, and lift an 880-kilogram drawbridge.

The final times decided which teams advanced, placing pressure on both speed and technique.

While the episode highlights teamwork and coordination, the challenge itself is rooted in physics — specifically, weight distribution, friction, leverage, and terrain resistance.

Physical: Asia — How Physics controlled the 2.2-tonne Castle Conquest Challenge

The Master explains the foundation of the task from the start, noting that the wagon is loaded with 1,400 kg of bags and crates and weighs 800 kg on its own.

The 2.2-tonne total creates a significant downward force on sand, a surface that naturally shifts under pressure.

Korea, Mongolia, and Japan all attempt to push and pull the load uphill, encountering the same mechanical limitations.

Sinking wheels and sand resistance

All three teams experienced wheel lock as the wagon attempted to climb the sand incline.

The sand collapses beneath the wheels, creating a bowl-shaped depression.

This increases the effective resistance the wagon must overcome.

Korea encounters this early. Seung-yeon says, 

“We couldn’t get a foothold. We just kept sinking into the sand.”

Min-jae adds that the cart “started to feel heavier” as the incline increased.

The combined weight compresses the sand, increasing static friction. With each failed push, the wheels burrow deeper.

Mongolia hits the same mechanical wall. Adiyasuren notes, 

“The wheels just sunk into the sand.”

Even with six people applying force, the cart pushes back with equal resistance.

Japan encounters the same limitation. When their empty cart stalls, Kana says, 

“In all my years of training, I’ve never experienced that level of resistance.”

All three countries unloaded the cart during key phases.

Removing sandbags and crates reduces mass, reducing both downward force and wheel sink depth.

Korea unloads twice; Mongolia unloads immediately; Japan unloads before its first push.

Gate Mechanics: Why the battering ram works

The castle gate is designed to resist frontal force, meaning contestants must generate high impact pressure.

Korea attempts multiple synchronized strikes, following “One, two… three!” counts to maximize force per hit.

Using a battering ram increases impact density by concentrating force along a small area.

Mongolia used targeted strikes and cracked the door open. Orkhonbayar explains, 

“Hitting the center of the door would make it harder to break. So instead we focused on one side.”

Applying force to a weaker structural point reduces the gate’s resistance, cracking it faster.

Japan’s ram fails because it hits the door straight-on. Yushin explains, 

“We made a big dent, but that was it. It wouldn’t open.”

Only when Katsumi suggests ramming with the cart does the combined forward momentum exceed the door’s breaking threshold.

Why the bridge lift required leverage, not strength

The final task involves raising an 880-kg drawbridge via rope-and-pulley.

Korea identified leverage as the key and pulled it open faster. Dong-hyun instructs, 

“If we’re using a pulley, we should treat it like tug-of-war. Pull straight back, as far back as we can go.”

Increasing distance increases the tension force on the rope, allowing the gate to rise.

Mongolia faced the same issue but could not lift the bridge by pulling alone.

Orgil proposed adding weight to the system.

His method — wrapping the rope around the battering ram and using its weight to pull the rope.

With four people pushing down on the log, the combined gravitational force amplified the pulling load.

With the ram's weight, it tightened the rope and lifted the bridge.

Japan struggled to understand the mechanism needed to lift the gate.

They spent more than 35 minutes attempting different approaches, but despite their efforts, they were never able to get the gate up.

Physical: Asia - A challenge built entirely around physics

Episode 11 of Physical: Asia demonstrates how moving a 2.2-tonne load depends on mechanical advantage, terrain management, strategic unloading, force concentration, and leverage.

Japan’s misunderstanding of the door-ramming and bridge-lifting mechanics slowed them down, and they couldn’t finish the challenge within the hour, resulting in their elimination from Physical: Asia.

The teams that understood these principles — or figured them out under pressure — completed Castle Conquest. Korea’s 17:53 time shows efficient execution.

Mongolia’s improvised technique shows adaptable reasoning. 

Stay tuned for more updates.