Question

When you jump from an elevated position you usually bend your knees upon reaching the ground, which makes the time of the contact about 10 times that of a stiff-legged landing. In this way the average force your body experiences is Group of answer choices about 10 times as great. more than 1/10 as great. about 1/10 as great. less than 1/10 as great.

Answer 1

Answer:

The correct option is c. about 1/10 as great

Explanation:

The problem can be understood by the concept of impulse. Impulse is a integral of force.

                                  Impulse = Force × Time

As when we bend our knees upon reaching the ground the time of contact is about 10 times that of a stiff-legged. so,

                                 $(Time)_{bend}$ = 10 × Time

So the force will be:

                                Force = $\frac{Impulse}{(Time)_{bend} }$

                                Force = $\frac{Impulse}{10* Time}$

                                Force = $\frac{1}{10}$ × $\frac{Impulse}{Time}$

Hence the force is one tenth of the total as seen by the calculation.