Final answer:
The impact of a car hitting a tree at 20 mph is four times greater than at 10 mph due to the square of the velocity in the kinetic energy formula.
Step-by-step explanation:
A car moving at 20 mph hits a tree with an impact that is linked to the kinetic energy it carries. The kinetic energy (KE) of a moving object is given by the equation KE = ½mv², where m is the mass, and v is the speed. When comparing the impact at two different speeds, we square the ratio of the speeds to determine the relative force of impact. Therefore, if a car is going 10 mph and then goes 20 mph, the impact at 20 mph is (20/10)² = 4 times greater than at 10 mph.