Que necesitas en español????
Drag is passive, therefore it does not act on gravity. Drag is a mechanical resistance to motion. If the motion in question was induced by gravity drag it can impede that motion, but has no effect on the gravity.
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Answer:


Explanation:
We have an uniform circular motion, therefore, the pebble’s speed is given by the distance traveled in a revolution
and the period (T), since this is the time pebble’s takes to complete a revolution:

The period is inversely proportional to the frequency:

So, we have:

Recall that the radius is the half of the diameter and one revolution per is equal to one Hz:

The centripetal acceleration is defined as:

The wavelength of the radio waves is 3.04 cm.
<h3>Calculation:</h3>
λf = c
λ = c/f
where,
λ = wavelength
c = speed of light
f = frequency
Given,
f = 98.6 MHz = 98.6 × 10⁶
c = 3 × 10⁸
To find,
λ =?
Put the values in the formula,
λ = c/f
λ = 3 × 10⁸/98.6 × 10⁶
= 0.0304 × 10² m
= 3.04 cm
Therefore, the wavelength of the radio waves is 3.04 cm.
Learn more about the calculation of wavelength here:
brainly.com/question/8422432
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Answer:

Explanation:
Given:
- original frequency of sound wave,

- speed of the sound source,

- original speed of sound wave from the source,

<u>According to the Doppler's effect:</u>

The sound is reflected from the wall and the source is moving towards the wall and observer is also riding the same source.
The velocity of the observer,

