Final answer:
The Coefficient of Restitution (COR) is a measure of an object's ability to regain its shape after being deformed, such as a ball bouncing after impact. COR is calculated as the square root of the ratio of the bounce height to the drop height. A COR of 1 signifies a perfectly elastic collision with no energy loss.
Step-by-step explanation:
Understanding the Coefficient of Restitution
The measure of the ability of an object, like a ball, to spring back to its original shape after being hit is the Coefficient of Restitution (COR). This concept is crucial in physics, especially when understanding the elastic properties of collisions. When you drop a ball, it bounces back due to its elasticity. The COR is defined as the ratio of the relative speed after impact to the relative speed before impact. For instance, when you perform an experiment dropping a tennis ball onto a racquet that's lying on the floor, you can calculate the COR by measuring the height the ball reaches after bouncing (h) and dividing it by the original height from which the ball was dropped (H). The formula applied is c = (h/H)¹/². If the COR is 1, the collision is perfectly elastic, meaning no kinetic energy is lost in the bounce, whereas a COR less than 1 indicates some energy loss in the collision.
For example, if a rubber ball bounces back to only 90% of its original height after hitting a hard floor, it reflects that some kinetic energy has been converted to other forms of energy like sound or heat, due to internal and external resistances such as air resistance and surface deformation. This is best explained as an inelastic collision where energy is not conserved.
When relating to real-life examples, new tennis balls used on a tennis court exhibit a COR of around 0.85, indicating that they are quite efficient in bouncing back but still lose some energy on impact with the floor.