Test your skills of deduction with the December 2025 edition of Riddle Me This: The Tipping Truck
A dump truck loaded with gravel is driving up a hill. As it climbs, the driver slowly raises the bed to dump the load out the back. But instead of losing the gravel, the truck tips backward. Why?
Click to Reveal Answer
Hopefully, to any engineer and anyone who has ever been or around a dump truck, the answer is obvious. As the bed is raised the load shifts toward the back, plus, depending upon the point of rotation of the truck bed, the center of gravity of the whole load goes up. This movement shifts the load, and hence its center of gravity backward and upward. The grade makes the whole truck plus load shift backward even with the load down. Add the raised and shifted load to the grade, it will reach a point where the center of gravity gets back of the point of rear wheel contact with the road. Once that happens, lo and behold, truck nose up into the air.