Help with Physics plz?

Question

A person jumps from a fourth-story window 15m above a firefightere's safety net. The survivor stretches the net 1m before coming to rest. What was the average deceleration experienced by the survivor when slowed to rest by the net? What would you do to make it safer (generate a smaller deceleration): would you stiffen or loosen the net? Explain

Place help answer include steps.
Thankyou.

Answer 1

Step 1: Use Torricelli's Equation to find the velocity when the person hits the net:
vf^2 = vi^2 + 2ad
vf^2 = 0 + 2 * 9.8m/s^2 * 15m
vf^2 = 294 m^2/s^2
vf = 17.146 m/s

Step 2: Use Torricelli's equation again to find the deceleration:
vf^2 = vi^2 + 2ad
0^2 = 294 m^2/s^2 + 2a * 1m
0 = 294 m^2/s^2 + 2a
294 = 2a
a = -147 m/s^2

Simpler method:
Note that both steps use Torricelli's equation, and flip vf and vi. The only real change is the acceleration:

Use vn to show velocity at time you hit the net:
vn^2 = vi^2 + 2gd1 (g for gravity)
vf^2 = vn^2 + 2ad2
Vf^2 = vi^2 + 2gd1 + 2ad2
Vf and vi = 0:
0 = 2g * 15 + 2a * 1
0 = 294 + 2a
2a = -294
a = -147 m/s^2 (Note: this would be termed 15 Gs, more than a fighter pilot usually experiences)

To make the net safer, you want to loosen it, so that the person decelerates over a longer distance, thus they decelerate slower.

Answer 2

Waves are many times defined with the aid of differences in some parameter with the aid of area and time—as an occasion, top in a water wave, stress in a valid wave, or the electromagnetic container in a mild wave. the fee of this parameter is named the amplitude of the wave, and the wave itself is a function specifying the amplitude at each and each factor. In any equipment with waves, the waveform at a given time is a function of the supplies (i.e., exterior forces, if any, that create or influence the wave) and preliminary situations of the equipment. in lots of situations (as an occasion, interior the classic wave equation), the equation describing the wave is linear. while it rather is real, the superposition thought could be utilized. meaning that the internet amplitude led to with the aid of 2 or extra waves traversing a similar area, is the sum of the amplitudes which could have been produced with the aid of the guy waves one after the different. as an occasion, 2 waves vacationing in the direction of one yet another will pass spectacular with the aid of one yet another with out any distortion on the different facet.