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Zina [86]
3 years ago
13

I just need help with these seven!

Physics
1 answer:
Anna [14]3 years ago
5 0
21. light changes its direction when travelling through a new medium because denser mediums have a higher angle of refraction.
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Which muscle disorder does donna’s doctor diagnose? donna is suffering from leg pain in which the calf muscles contract involunt
Kay [80]
Donna's doctor must have diagnosed her with muscle cramps. With the given symptoms above, it is likely that she is experiencing muscle cramps. Muscle cramps most likely happen when the individual experiencing it is lack of fluid intake, causing the muscles to tighten causing pain and for the muscle to contract involuntarily.
7 0
3 years ago
Read 2 more answers
Select the correct answer.
Vesna [10]

Answer:

C

Explanation:

Radiant= list onto solar panels, Electric= solar into power, Radiant= Electric into light

8 0
3 years ago
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HELPP ME IN PHYSICS +15 POINTS!! <br> But a right answer not links or I’ll report. -_-
frozen [14]

The answer shud be 31 . 14m

8 0
3 years ago
A helicopter starting on the ground is rising directly into the air at a rate of 25 ft/s. You are running on the ground starting
rusak2 [61]

Answer:

The rate of change of the distance between the helicopter and yourself (in ft/s) after 5 s is \sqrt{725} ft/ sec

Explanation:

Given:

h(t) =  25 ft/sec

x(t) = 10 ft/ sec

h(5) = 25 ft/sec . 5 = 125 ft

x(5) = 10 ft/sec . 5 = 50 ft

Now we can calculate the distance between the person and the helicopter by using the Pythagorean theorem

D(t) = \sqrt{h^2 + x^2}

Lets find the derivative of distance with respect to time

\frac{dD}{dt} (t)  = \frac{2h \cdot \frac{dh}{dt} +2x \cdot\frac{dx}{dt}} {2\sqrt{h^2 + x^2}}

Substituting the values of h(t) and  x(t) and simplifying we get,

\frac{dD}{dt}(t) = \frac{50t \cdot \frac{dh}{dt} + 20 \cdot \frac{dx}dt}{2\sqrt{625\cdot t^2 + 100 \cdot t^2}}

\frac{dh}{dt} = 25ft/sec

\frac{dx}{dt} = 10 ft/sec

\frac{Dd}{dt} (t) = \frac{1250t +200t}{2\sqrt{725}t}  = \frac{725}{\sqrt{725}}  = \sqrt{725} ft / sec

5 0
3 years ago
Photovoltaic cells: a) have become more economical to produce and use over the past 25 years. b) are the most efficient means of
Yanka [14]

Photovoltaic cells are the most efficient means of converting solar energy to electricity. Option b is correct.

<h3>What is a cell?</h3>

A cell is a voltage and current-producing device that consists of a single anode and cathode separated by an electrolyte.

One or more cells can make up a battery. One cell, for example, is one AA battery.

Light intensity on a solar cell is often measured in "suns," with one sun roughly equivalent to 1 kW/m².

Concentrated sunlight improves the ratio of current generated while the device is lighted vs when it is dark, hence enhancing output voltage and efficiency.

Photovoltaic cells are the most efficient means of converting solar energy to electricity.

Hence, option b is correct.

To learn more about the cell refer to:

brainly.com/question/3142913

#SPJ1

8 0
2 years ago
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