Force is a physical magnitude which helps us to understand the appearance of our world.  Everything which surrounds us is subject to interactions with other bodies (FORCES) and due to their balance or lack of balance the world has the appearance that we experience.

The basis of most scientific progress, critical for the development of our society, like the construction of bridges, aeroplanes..., is based on the mastery and use of forces.

Push the block from under the spring. Do it several times and carefully observe the movement of the spring.

You will find that:

The tendency to contract (orange arrow) is smaller the less the spring is stretched. The more the string is stretched, the greater the tendency (orange arrow) to recover its position of equilibrium.

Why does the spring stretch? Has the weight of the suspended body (red arrow) anything to do with it? When does the spring stop stretching?

We will answer these questions and many others in this unit.

SOME EFFECTS OF THE FORCES

Place the cursor over the red object and slide it downwards several times. What should we observe as we stretch it more?  ...that we also have to exert a greater force. Explanation A body (you) is interacting with another body (the spring) and the effect is to stretch it.