E. all of the above
An umbrella tends to move upward on a windy day because _<span>A. buoyancy increases with increasing wind speed </span>
<span>B. air gets trapped under the umbrella and pushes it up </span>
<span>C. the wind pushes it up </span>
<span>D. a low-pressure area is created on top of the umbrella </span>
Answer:
V = λ f (wavelength * frequency)
λ = V / f = 343 m/s / 262 / s = 1.3 m
If energy could<span> be created or </span>destroyed<span>, all of our ideas of how the world works ... Historically, of course </span>not<span> all the forms of energy were known to begin with. ... too messy or complicated to make sense, we </span>would have<span> had to give up the law. ... </span>can<span> be converted into rest </span>mass<span> and back again (particle physicists </span>do<span> this </span><span>every )</span>
<h3><u>Answer;</u></h3>
A. 4
<h3><u>Explanation;</u></h3>
- <em><u>The period of a wave or periodic time is the time taken for a complete oscillation to occur. </u></em>For example its is the time taken between two successive crests or troughs.
- <em><u>The beats or oscillation that occur in one second represents the frequency. Frequency is the number of complete oscillations or beats in one second in a wave.</u></em>
- Frequency, measured in Hertz is given by the reciprocal of the periodic time.
- Thus; <u><em>Frequency or beats per second = 1/(1/4) = 4</em></u>
- <u><em>Hence , 4 beats per second</em></u>