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gogolik [260]
3 years ago
11

Many physical quantities are connected by inverse square laws, that is, by power functions of the form f(x)=kx^(-2). In particul

ar, the illumination of an object by a light source is inversely proportional to the square of the distance from the source. Suppose that after dark you are in a room with just one lamp and you are trying to read a book. The light is too dim and so you move halfway to the lamp. How much brighter is the light?
Physics
1 answer:
goldenfox [79]3 years ago
3 0

Answer:

  • 4 times

Explanation:

Since the equation for the illumination of an object, i.e. the brightness of the light, is <em>inversely proportional to the square of the distance from the light source</em>, the form of the function is:

  • f(x) = k.x⁻²

Where x is the distance between the object and the light force, k is the constant of proportionality, and f(x) is the brightness.

Then, if you move halfway to the lamp the new distance is x/2 and the new brightness (call if F) is :

F=k(x/2)^{-2}=\frac{k}{(x/2)^2}= \frac{k}{x^2}. 4=f(x).4

Then, you have found that the light is 4 times as bright as it originally was.

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Answer: the poles

Explanation:

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2 years ago
A rock group is playing in a bar. Sound emerging from the door spreads uniformly in all directions. The intensity level of the m
LekaFEV [45]

Answer:

1779299.7m

Explanation:

From formulas in acoustic sound, we know that sound intensity is inversely proportional to the square of the distance away.

Thus;

I2/I1 = r2²/r 1²

So,

∆L = 10 log (I2/I1)

Where ∆L is the intensity of music and r1 and r2 are distances away.

∆L=10log 10(r1²/r2²)

∆L=10log 10(r1/r2)²

∆L= - 20log 10(r1/r2)

r2 = r1•10^(-∆L/20)

​From the question,

∆L = 116 Db

r1 = 2.82m

Thus,

r2 = 2.82 x 10^(116/20)

r2 = 2.82 x 630957.34 = 1779299.7m

5 0
4 years ago
Read 2 more answers
A small metal sphere weighs .28 N in air and has a volume of13
Ray Of Light [21]

To solve this problem we will start by considering how to calculate the apparent weight. On the sphere this will then be given that the real weight is the sum of the apparent weight and the Buoyant Force. Therefore we will have to

W_T = W_A + F_B

Here

W_T= True Weight

W_A= Apparent Weight

F_B= Buoyant Force

If we seek to find the apparent weight we will have to,

W_A = W_T-F_B

W_A = 0.28N - V\rho g

Remember that

V = Volume (Volume Sphere)

\rho= Density (At this case water density)

g = Gravitational acceleration

W_A = 0.28N - (13*10^{-6}m^3)(1000kg/m^3)(9.8)

W_A = 0.1526N

Therefore the apparent weight will be 0.1526N

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4 years ago
A ski jumper travels down a slope and leaves
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Question seems to be missing. Found it on google:

a) How long is the ski jumper airborne?

b) Where does the ski jumper land on the incline?

a) 4.15 s

We start by noticing that:

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v_x = 28 m/s

and the distance covered along the horizontal direction in a time t is

d_x = v_x t

- The vertical motion of the skier is a uniformly accelerated motion, with initial velocity u_y = 0 and constant acceleration g=9.8 m/s^2 (where we take the downward direction as positive direction). Therefore, the vertical distance covered in a time t is

d_y = \frac{1}{2}gt^2

The time t at which the skier lands is the time at which the skier reaches the incline, whose slope is

\theta = 36^{\circ} below the horizontal

This happens when:

tan \theta = \frac{d_y}{d_x}

Substituting and solving for t, we find:

tan \theta = \frac{\frac{1}{2}gt^2}{v_x t}= \frac{gt}{2v_x}\\t = \frac{2v_x}{g}tan \theta = \frac{2(28)}{9.8} tan 36^{\circ} =4.15 s

b) 143.6 m

Here we want to find the distance covered along the slope of the incline, so we need to find the horizontal and vertical components of the displacement first:

d_x = v_x t = (28)(4.15)=116.2 m

d_y = \frac{1}{2}gt^2 = \frac{1}{2}(9.8)(4.15)^2=84.4 m

The distance covered along the slope is just the magnitude of the resultant displacement, so we can use Pythagorean's theorem:

d=\sqrt{d_x^2+d_y^2}=\sqrt{(116.2)^+(84.4)^2}=143.6 m

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