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agasfer [191]
4 years ago
9

A ball is thrown directly downward with an initial speed of 8.75 m/s, from a height of 21.0 m. after what interval does the ball

strike the ground

Physics
1 answer:
gayaneshka [121]4 years ago
8 0
There you go!
as it is unnecessary to find velocity, so use the equation with v
remember to take all directions downwards as it is more convenient to calculate
after substituting the values, you have to reject the negative answed as time must be+
:)

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Suppose that the sun shrank in size but that its mass remained the same. What would happen to the orbit of the earth?
Minchanka [31]

Answer:

Nothing

Explanation:

The radius of the orbit of the Earth does not depend on the radius of the sun.

In fact, the gravitational attraction between the Earth and the Sun provides the centripetal force that keeps the Earth in orbit:

G\frac{Mm}{r^2} = m\frac{v^2}{r}

where

G is the gravitational constant

M is the mass of the sun

m is the mass of the Earth

r is the radius of the orbit of the Earth

v is the orbital speed of the earth

Re-arranging the equation for r:

r=\frac{GM}{v^2}

Also,

v=\omega r

where \omega is the angular velocity of the Earth's orbit. So we can rewrite the equation as

r=\frac{GM}{\omega^2 r^2}\\r^3 = \frac{GM}{\omega^2}

As we see, the radius of the orbit of the Earth, r, does not depend on the mass of the Sun, so if the sun shrank in size, the orbit remains the same.

6 0
3 years ago
in terms of the wavelength of the sound wave, about how far below the open end of the resonance tube is the first resonant posit
notka56 [123]

The first resonant position below the open end of the resonance tube is; <em><u>one-quarter of the wavelength</u></em>

In the event of the first resonant position in a resonance tube, there will be a maximum air displacement which is only one antinode right at the open end where the motion is constrained.

However, there will be no displacement at the closed end which means another one node right at the closed end where air is halted.

This means that the standing wave will have one-quarter of the wavelength in the test tube.

Thus;

L = ¼λ

Read more at; brainly.com/question/17086525

8 0
2 years ago
A man is sitting on a chair with wheels. He grabs a 2.1 kg book from the desk and throws
geniusboy [140]

The speed of the man and the chair after the book is thrown is 0.2 m/s.

The given parameters:

  • <em>mass of the book, m₁ = 2.1 kg</em>
  • <em>speed of the book, u₁ = 7.2 m/s</em>
  • <em>mass of the man, M = 70 kg</em>
  • <em>mass of the book, m = 9.2 kg</em>

<em />

The total mass of the man and the book is calculated as follows;

m₂ = 70 kg + 9.2 kg

m₂ = 79.2 kg

The speed of the man and the chair after the book is thrown is determined by applying the principle of conservation of linear momentum;

m_1 u_1 = m_2u_2\\\\u_2 = \frac{m_1u_1}{m_2} \\\\u_2 = \frac{2.1 \times 7.2}{79.2} \\\\u_2 = 0.2 \ m/s

Thus, the speed of the man and the chair after the book is thrown is 0.2 m/s.

Learn more about conservation of linear momentum here: brainly.com/question/7538238

8 0
3 years ago
If an object falls far enough, it will reach terminal velocity. At this velocity, the force of air
love history [14]

Answer:

The object will contine to fall, but at a constant velocity.  There will be no more acceleration.

Explanation:  When the force of gravity is equal to the reverse force of air resistance, there will will be no net force on the falling obect.  F = ma, and F (net) = 0.  It will continue at the same speed until those forces become imbalanced again (such as when the force pushing up from the ground is greater than the force of gravity pulling it down).  The metric term for this sudden resistance is "crash/bang/clunk/yieouch."

3 0
3 years ago
12. The diameter of a circle is 2.42m. Calculate its<br>area in proper significant figure​
Sever21 [200]

Answer:

A = 4.6 [m²]

Explanation:

The area of a circle can be calculated by means of the following equation.

A=\frac{\pi }{4} *D^{2}

where:

A = area [m²]

D = diameter = 2.42 [m]

Now replacing:

A=\frac{\pi }{4} *(2.42)^{2} \\A = 4.6 [m^{2} ]

7 0
3 years ago
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