Science of Levers

A lever is a ‘simple machine consisting of a relatively rigid, barlike body that may be made to rotate about an axis’, (Hall, p.430). To put it into everyday life terms, a lever is used ‘to lift heavy weights with the least amount of effort.’ (Ryan, 2010). There are three different levers.

First Class

‘Lever positioned with the applied force and the resistance on opposite sides of the axis of rotation’ (Hall, p.431). [figure 3]

For example: A workman uses a trolley to move the large packing case. The fulcrum is the wheel. (Ryan, 2010).

Second Class

‘Lever positioned with the resistance between the applied force and the fulcrum’ (Hall, p.431). [figure 3]

For example: The gardener uses a wheel barrow to lift tools and garden waste. The load is in the centre of the barrow. (Ryan, 2010).

Third Class

‘Lever positioned with the applied force between the fulcrum and the resistance’ (Hall, p.432). [figure 3]

For example: The fisherman catches the ‘fish’ which becomes the load at the end of the lever. (Ryan, 2010).

The most effective lever to use in a tennis serve to get maximal speed/force would be a third class lever. The fulcrum would be at the legs, the force of the torso and arms and the load is the tennis racket. This lever uses minimal effort, but produces speed so would therefore be appropriate and withstanding in a lengthy game of tennis.

However, the most effective lever in a tennis serve to have maximum control and accuracy would be a middle grip (first class lever) as it would allow the server to feel more balanced and in control of their serve, allowing a higher chance of the tennis ball to go in the desired direction.

 

 

 

 

FIGURE 3