# Persuasive

QUESTIONS ON HOOKE’S LAW |
| |1. A spring is 20 cm long when a load of 10 N is hanging from it, and 30 cm long when a load of 20 N is hanging from it. Draw a graph to work out the length of the spring when:
a] there is no load on it;
b] there is a load of 5 N on it.
(Plot x = load, y = spring length)

2. In a spring experiment, the results were:

|load (N)                   |0       |1       |2       |3       |4       |5       |6         |7         |
|length (mm)               |50     |58     |70     |74     |82     |90     |102       |125       |
|extension (mm)             |       |       |       |       |       |       |           |           |

a] What is the length of the spring when unstretched?
b] Copy and complete the table.
c] Plot a graph of the data.   (Plot x = load, y = spring extension)
d] One of the results is wrong.
(i) Which? (ii) What should the result be?
e] Mark the elastic limit on your graph.
f] What load would give an extension of 30 mm?
g] What would be the spring length for a load of 4.5 N?

3. Some students carry out an experiment to find out how a spring stretched when loads were added to it.
a] Draw a labelled diagram to show what is meant by the extension of the spring.

The results of the experiment are shown in the table. One of the readings is incorrect.

|load (N)                   |0       |2       |4       |6       |8       |10       |12       |14       |
|extension (mm)             |0       |16       |32       |58       |64       |80       |96       |112     |

b] Use these results to plot a graph.   (Plot x = load, y = spring extension)
c] Use your graph to find (i) the extension when the load is 3 N;
(ii) the load which produces and extension of 40 mm.
d] Label the incorrect point on the graph with the letter E.

4. (EXTENSION) An engineer needs to know how far a long beam will sag under a load. The table shows some results:

|load (N)             |1000             |2000...