A 55-kg person lands on firm ground after jumping from a height of 2.8 m.

Explanation:

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Potential energy?

3018.4

Explanation:

So this velocity just before reaching the ground, the final equals square root of two times G times H. So gs 9.8 m per second squared H is 2.8 m. So it gives the velocity of 7.41 m per second squared. That's the velocity right before touching the ground. So to find the impulse required to come to rest here, we just do mass times the velocity minus zero. So zero is the final momentum, final velocity zero. So that makes the final momentum zero. So we multiply the mass with the velocity before touching the ground and after. And subject zero. That's the momentum after touching the ground. So we multiply mass 55 kg. At 7.41 velocity we got 407.45.  kilograms meters per second of impulse. we know that the force will be larger for stiff stiff flex compared to bend flex. Because the stiff flex. Bring the object to rest in a short amount of time and distance. So in part C, that's calculate for stiff flex. The stopping distance, Delta Y. Is 0.1 m. This one centimeter. So we can calculate the acceleration of the body when it comes to rest.  From the moment it touches the ground.  equals v squared over two times Delta Y. So  we use the square is 54.88. The 7.41 square divided by two times 0.01 gives us an explosion of 2744 m/s square. So you multiply this acceleration by the mass to get the force so force equals mass times acceleration gives us a large force,  159 20 newtons. Then for bent legs, repeat the same process with a different delta Y, delta Y of 200.5 m. So that's 50 centimeters and calculate acceleration the same process. Just use a different value of delta Y. And we get as much smaller acceleration 54.88 m per second square. And the force experience would just be mass times acceleration. That gives us 3018.4 newton's a lot smaller than for stiff flex.

c)as speed changes, wavelength and frequency change.

everything changes!