CDL General Knowledge TestTransporting Cargo SafelyMedium
A driver is transporting a liquid bulk load in a partially filled tank. Which of the following forces presents the greatest risk during braking or turning?
- ACentrifugal force, pushing the liquid outwards in turns.
- BFriction, resisting the flow of the liquid.
- CInertia, causing the liquid to slosh back and forth.
- DGravitational force, pulling the liquid downwards.
Show answer & explanationAnswer & explanation
Correct answer: C. Inertia, causing the liquid to slosh back and forth.
Inertia, specifically the 'sloshing' effect (surge) of liquid in a partially filled tank, is the greatest risk. As the vehicle brakes, the liquid surges forward. As it accelerates, it surges backward. In turns, it surges to the side. This movement can drastically shift the vehicle's center of gravity, leading to instability and loss of control.
Why the other options are wrong
- A. Centrifugal force is a factor in turns, but the sloshing due to inertia (surge) is a more pronounced and dangerous effect in partially filled tanks.
- B. Friction resists motion and is not the primary destabilizing force in this scenario.
- D. Gravitational force is constant and predictable; it does not cause sudden, destabilizing shifts in a partially filled tank.
Liquid Bulk Surge
The forward and backward motion of liquid in a partially filled tank caused by inertia during acceleration and deceleration.
- Most dangerous in partially filled tanks.
- Causes sudden shifts in vehicle's center of gravity.
- Requires careful braking and acceleration.
Memory trick: Sloshing liquid, shifting weight, makes driving tricky.