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Basic Requirements

A grasshopper jumps by extending its back legs from a folded postion, so that they thrust against the ground.

To get a good jump requires two things.

[Science stuff: equations of motion and some facts and figures]

 

too weak

too slow

just right

Note: these cartoons are only for illustration - they are not tracings from real jumping grasshoppers.

So remember, a good jump means that the legs must push against the ground with high force, and high speed.

To be precise (or reasonably so), a typical grasshopper weighing 2-3 gm will thrust against the ground with a force which peaks at about 30 gms when the legs are half extended, to give it a final take-off velocity of about 3 m.s-1.

[For future reference: note how in the good jump there is a slight delay between the initial crouch and the actual jump. This delay is crucial, as we shall see later.]

The ultimate source of this push comes from the contraction of the muscles inside the leg, so let's start off by seeing how the muscles make the leg move...


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