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garri49 [273]
3 years ago
14

A 5 kg rock is dropped down a vertical mine shaft. How long does it take to reach the bottom, 79 meters below?

Physics
1 answer:
likoan [24]3 years ago
7 0

Answer:

The time for the rock to reach the bottom is 4.02 seconds.

Explanation:

Given;

mass of the rock, m = 5 kg

height of the rock fall, h = 79 meters

The time to drop to the given height is given by;

t = \sqrt{\frac{2h}{g} }

where;

t is the time to fall to the bottom

g is acceleration due to gravity = 9.8 m/s²

t = \sqrt{\frac{2h}{g} } \\\\t =  \sqrt{\frac{2*79}{9.8} }\\\\t = 4.02 \ s

Therefore, the time for the rock to reach the bottom is 4.02 seconds.

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Answer:

<em>His angular velocity will increase.</em>

Explanation:

According to the conservation of rotational momentum, the initial angular momentum of a system must be equal to the final angular momentum of the system.

The angular momentum of a system = I'ω'

where

I' is the initial rotational inertia

ω' is the initial angular velocity

the rotational inertia = mr'^{2}

where m is the mass of the system

and r' is the initial radius of rotation

Note that the professor does not change his position about the axis of rotation, so we are working relative to the dumbbells.

we can see that with the mass of the dumbbells remaining constant, if we reduce the radius of rotation of the dumbbells to r, the rotational inertia will reduce to I.

From

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since I is now reduced, ω will be greater than ω'

therefore, the angular velocity increases.

5 0
3 years ago
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Setler79 [48]

Answer:

Speed of light

Explanation:

The famous Einstein's equation is:

E=mc^2

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In this equation, Einstein summarized the following fact: mass can be converted into energy, and the amount of energy released in such a process is given by the equation.

An example of application of this equation is the nuclear fusion process. In a nuclear fusion, two lighter nuclei combine into a heavier nucleus. However, the mass of the heavier nucleus is slightly less than the sum of the masses of the two original nuclei: some of the mass of the original nuclei has been converted into energy, accorging to the previous equation.

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Which of the following statements is true? A. All metals are magnetic. B. All the magnets are made of iron. C. Earth is a giant
harina [27]

C. Earth <em>is </em>a giant magnet

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Answer:

YFy = 0 = Ffsinθ + Fncosθ - Fw

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From the base of the vector Fn, draw a vertical line. the small angle between this line and Fn is also theta. The component of Fn in the vertical direction is Fncos(theta).

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Acceleration is zero if
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It’s doesn’t change meaning it’s 0
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