Question 1 Report
A gymnast lands on a thick soft mat instead of a hard floor. The mat reduces the force on the gymnast's legs.
How does the mat achieve this?
When the gymnast lands, her momentum changes from a downward value to zero. This change in momentum is the same regardless of whether she lands on a mat or a hard floor, because her mass and landing speed are the same in both cases.
The relationship between force, time, and momentum change is:
\[F = \frac{\Delta p}{\Delta t}\]
The thick soft mat compresses on impact, and this compression takes time. By increasing the time \(\Delta t\) over which the gymnast decelerates, the mat reduces the average force on her legs. The mat does not absorb all the kinetic energy before landing (the gymnast still makes contact), nor does it reduce her mass or her change in momentum.
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