Use this formula for an object starting from rest and accelerating:
Distance = (1/2) (acceleration) (time)²
In this problem, the distance is 40 meters, and acceleration is gravity.
So . . .
40 m = (1/2) (9.8 m/s²) (time)²
Divide each side by (4.9 m/s²) :
time² = (40 m) / (4.9 m/s²)
time² = 8.16 sec²
Take the square root of each side :
√(time²) = √(8.16 sec²)
time = 2.86 seconds
Round it to 2.9 sec <em>(choice B)</em>
Sure: ths is called protyping and lets yu get a sende fo the effeciveness tof the cahnge and the cost of the change.
<span>A - just like the scientific principle syu what to know what other know or have learned. Example would it be silly to build a nuclear power de-salinatiztion plant when a dam in the mountains wuld dothe savme thng and perhaps have the advatage of using local labor and preveinting floods and givng of hydro eletic power. </span>
<span>A a process is a technological soultion it uses tools, machines, chemical to effect an otu come.</span>
To get this we need to know how long he was traveling. To know that we need to solve for the time it took for him to hit the ground. This is given by the vertical height he started at and the equation of motion for falling objects. The position function is
Y= -(9.8/2)t^2 + 50 = 0
t=3.19s
That's how long he's in the air. When he hits the ground he stops moving forward so this is also the amount of time he was moving at 100m/s horizontally. Now use speed distance relationship
X=vt
And solve for v
100m/3.19s = 31.35m/s
Through the 1/r law, it was concluded that for the sound intensity or pressure is directly proportional to distance or radius. That is,
p = k/r
where k is the proportionality constant. If the distance of a sound wave is quadrupled then, the intensity of the sound is decreased to 1/4 of its original value.
