STUDY THE ELASITICITY
AIM
1 Study the relation between the force applied on a spring and the extension of the spring.
2 Study the relation between the force applied on a rubber band and the extension of the rubber band.
EQUIPMENT
A stand, a spring, a rubber band, a meter, weights and a spring balance
BACKGROUND
Up to the point X the force F is directly proportional to e beyond this point the proportional is lost. If the point X is passed, the spring can become permanently deformed in such a way that when the weights are removed the spring will not go back to its original length. In the region of proportionality, we can write F=kx where k is a constant whose value will depend on the particular spring. For this reason, k is called the spring constant. This spring behavior is a specific example of a more general rule known as Hooke’s Law after the 17th century physicist Robert Hooke. Therefore, the region of proportionality is often referred to as the “Hookey region” or “elastic limit”. We can see that a spring can be calibrated to measure force and no doubt your physics laboratory has several so-called “Newton meters”. However, you will discover that these Newton meters do not provide a particularly reliable method of measuring force.
