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4 years ago

Why do people get sunburned by UV light ?

Physics

1 answer:

solong [7]4 years ago

8 0

Answer: Lack of melanin in the skin.

Explanation: The amount of melanin in your body is determined genetically. Some people dont produce enough melanin to protect their skin well. Eventually the UV causes the skin to burn, causing redness, swelling and pain.

PLEASE RATE 5 STARS AND VOTE AS BRAINLIEST:)

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que 2. Why do we keep frequency constant instead of keeping vibrating length constam second law of vibrating string?

ella [17]

Answer:

The second law of a vibrating string states that for a transverse vibration in a stretched string, the frequency is directly proportional to the square root of the string's tension, when the vibrating string's mass per unit length and the vibrating length are kept constant

The law can be expressed mathematically as follows;

$f = \dfrac{1}{2\cdot l} \cdot \sqrt{\dfrac{T}{m} }$

The second law of the vibrating string can be verified directly, however, the third law of the vibrating string states that frequency is inversely proportional to the square root of the mass per unit length cannot be directly verified due to the lack of continuous variation in both the frequency, 'f', and the mass, 'm', simultaneously

Therefore, the law is verified indirectly, by rearranging the above equation as follows;

$m = \dfrac{1}{ l^2} \cdot \dfrac{T}{4\cdot f^2} }$

From which it can be shown that the following relation holds with the limits of error in the experiment

m₁·l₁² = m₂·l₂² = m₃·l₃² = m₄·l₄² = m₅·l₅²

Explanation:

8 0

3 years ago

Compare an object sliding across carpet and that same object sliding across a bare floor. Why is the object quicker to slow down

My name is Ann [436]

Because of friction. Hope this helps. Mark brainliest:)

5 0

4 years ago

Read 2 more answers

Which formation moves sediment and erodes rock?

borishaifa [10]

Answer:

Explanation:

7 0

3 years ago

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The outer layer of cable on a cable reel is 16.2 cm from the center of the reel. The reel is initially stationary and can rotate

ahrayia [7]

Answer:

B. w=12.68rad/s

C. α=3.52rad/s^2

Explanation:

We can solve this problem by taking into account that (as in the uniformly accelerated motion)

$\theta=\omega_{0}t+\frac{1}{2}\alpha t^{2}\\\theta = \frac{s}{r}$ ( 1 )

where w0 is the initial angular speed, α is the angular acceleration, s is the arc length and r is the radius.

In this case s=3.7m, r=16.2cm=0.162m, t=3.6s and w0=0. Hence, by using the equations (1) we have

$\theta=\frac{3.7m}{0.162m}=22.83rad$

$22.83rad=\frac{1}{2}\alpha (3.6s)^2\\\\\alpha=2\frac{(22.83rad)}{3.6^2s}=3.52\frac{rad}{s^2}$

to calculate the angular speed w we can use $\alpha=\frac{\omega _{f}-\omega _{i}}{t _{f}-t _{i}}\\\\\omega_{f}=\alpha t_{f}=(3.52\frac{rad}{s^2})(3.6)=12.68\frac{rad}{s}$

Thus, wf=12.68rad/s

C) We can use our result in B)

$\alpha=3.52\frac{rad}{s^2}$

I hope this is useful for you

regards

3 0

3 years ago

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A sample of ancient granite crust is dated using potassium-40. Scientists find that 50% of the potassium-40 has decayed to form

damaskus [11]

The find the approximate age of the granite one must know the half-life of potassium-40. The half-life of an element is the period of time in which half atoms of the same substance changes into the isotope of the element. The isotope of potassium-40 is Argon 40. Potassium-40 has a half-life of approximately 1.3 billion years. The rock is approximately 1.3 billion years old.

3 0

3 years ago

Read 2 more answers