Final answer:
To absorb shock when riding over an object, bending your legs or rolling on the ground increases the time over which the force acts, leading to a smaller force impact.
Step-by-step explanation:
When you ride over an object on the road, you can absorb some of the shock by bending your legs or rolling on the ground. This method increases the time over which the force acts, leading to a smaller force impact compared to landing stiff-legged. An example from nature demonstrating this principle is a kangaroo's hopping; the shock of each hop is cushioned by the bending of its hind legs, thus distributing the force over a longer period and reducing its impact.