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Elephant on the Bridge/Lesson Document: Difference between revisions
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# The force of reaction from the bridge pushing upwards on the elephant’s feet (see insert for fuller explanation). | # The force of reaction from the bridge pushing upwards on the elephant’s feet (see insert for fuller explanation). | ||
[[Image:elephants foot.png|300x300px]] | |||
But because the bridge sags, its surface is not horizontal. This means that there is: | But because the bridge sags, its surface is not horizontal. This means that there is: | ||
Friction between the elephant’s feet and the surface of the bridge; | |||
3. Friction between the elephant’s feet and the surface of the bridge; | |||
The net effect of all these forces acting on the elephant is to keep it stationary in the position shown in the picture. | The net effect of all these forces acting on the elephant is to keep it stationary in the position shown in the picture. | ||
The net force (or resultant force, as it is called by science) upon something is the sum total of all the various forces acting upon it, i.e. all these forces are added together and regarded as a single force. | The net force (or resultant force, as it is called by science) upon something is the sum total of all the various forces acting upon it, i.e. all these forces are added together and regarded as a single force. | ||
Since the elephant is stationary, there cannot be any net force acting on it, i.e. the resultant force on the elephant must be zero. | Since the elephant is stationary, there cannot be any net force acting on it, i.e. the resultant force on the elephant must be zero. | ||
