Gravitational Forces

The spring can extend (stretch) under the influence of an applied force. According to Hooke’s law: elongation is directly proportional to the magnitude of the applied force. If we want the Earth’s gravitational force to act on the spring, we suspend a weight (of known value) on the spring. The heavier the weight we hang, the more the spring will elongate. Care must be taken that the weight is not too great as it will damage the spring.

1. Analyse the image that shows the results of measurements made with a spring.

Philip took several measurements using a spring, ruler and weights. He placed the ruler along the spring so that he could measure its length in relation to the weight load on the spring.

Based on this experiment, Philip concluded that the gravitational force of the Earth acts on gravity. He calculated the magnitude of the force by applying the formula Fg = m * g (g = 10 N/kg) and recorded the results in a table. The table can be viewed in Excel.

2. Plot a graph of the dependence of spring length (l) on spring load (m). Work in Excel.

3. Answer the questions based on the data from the graph:

• What is the length of the spring without load?
• How much force corresponds to a load of 50 g?
• What would be the length of the spring under a force of 0.6 N?

4. Discuss and conclude on the relationship between the mass of the weight and the extension of the spring.