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ira
12 days ago
7

An object moving due to gravity can be described by the motion equation y=y0+v0t−12gt2, where t is time, y is the height at tha

t time, y0 is the initial height (at t=0), v0 is the initial velocity, and g=9.8m/s2 (the acceleration due to gravity). If you stand at the edge of a cliff that is 75 m high and throw a rock directly up into the air with a velocity of 20 m/s, at what time will the rock hit the ground? (Note: The Quadratic Formula will give two answers, but only one of them is reasonable.)
Physics
1 answer:
Softa [913]12 days ago
8 0

Answer:

t=6.4534 s

Explanation:

This problem requires applying concepts related to objects in free fall.

Our known variables consist of initial height, initial velocity, and the acceleration attributed to gravity:

y_{0}=75m

v_{oy} =20m/s

g=9.8 m/s^{2}

At the conclusion of the fall, the rock reaches the ground meaning the final height y=0m

y=y_{o}+v_{oy}*t-\frac{1}{2}gt^{2}

If we analyze the equation:

0=75m+(20m/s)t-\frac{1}{2}(9.8m/s^{2})t^{2}

This represents a standard Quadratic Formula, which we can resolve using:

t=\frac{-b ± \sqrt{b^{2}-4ac } }{2a}

a=-4.9\\b=20\\c=75

t=\frac{-(20) + \sqrt{(20)^{2}-4(-4.9)(75) } }{2(-4.9)}=-2.37s

t=\frac{-(20) - \sqrt{(20)^{2}-4(-4.9)(75) } }{2(-4.9)}=6.4534s

Given that time cannot be negative, the valid solution is

t=6.4534s

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This law can be utilized for the needle, allowing us to compute the pressure difference between point P and the needle's end. In this scenario, we have:

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For t > = to, the expression (2t/to-1) yields a value greater than 1, indicating that the distance expands as time progresses.

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