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3 years ago

Explain why the intensity of the light in a flashlight beam decreases as the flashlight moves farther away.

Physics

1 answer:

Karolina [17]3 years ago

7 0

Ir=Initial Intensity/Area of spread=Io4πr2
Ir∝1r2

It is seen from this expression that intensity is inversely proportional to the square of the distance. As we move away from the light source the intensity decreases at the rate of square of the distance from the source.

Brightness being the perception of intensity. more the intensity more bright the object is perceived and vice versa.

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An archer fish launches a droplet of water from the surface of a small lake at an angle of 70° above the horizontal. He is aimin

Norma-Jean [14]

Answer:

a). v=2776 m/s

Explanation:

The speed of the water droplet for the fish be successful is

Taking the distance in axis 'x' and 'y'

$x_{tx}=40cm\frac{1m}{100cm}=0.40m\\x_{ty}=23cm\frac{1m}{100cm}=0.23m$

The time is the velocity in axis 'x' with the angle 70 so

$t=\frac{0.40m}{v_{x}*cos(70)}$

Now using the time in terms of velocity the motion in axis 'y' can find the velocity to be the fish successful

$x_{yf}=x_{yo}+v_{o}*t+\frac{1}{2}*g*t^{2}\\0.23m=0.40m\frac{vo*sin(70)}{vo*cos(70)} +\frac{1}{2}*9.8*(\frac{0.40}{vo*cos(70)} )^{2}\\0.23m=0.40m*vo*tan(70)+4.9*(\frac{0.16m^{2} }{vo^{2} *cos(70)^{2} }) \\vo^{2}cos(70)^{2}=\frac{0.16m^{2} }{0.177}\\vo=\sqrt{\frac{0.9021}{cos(70)^{2}}} \\vo=2.776 \frac{m}{s}$

4 0

3 years ago

When is an atom stable? A. when it has a full outer orbit. B. when it has the same amount of elections as protons. C. when it ha

balu736 [363]

B when the electrons and protons are the same amount

3 0

3 years ago

Read 2 more answers

Find the mass of a football player who's momentum is 630 kg•m/s backward and. is traveling at 7 m/s.

Setler [38]

Answer:

<h2>The answer is 90 kg</h2>

Explanation:

In order to find the mass of the football we use the formula

$m = \frac{p}{v} \\$

where

p is the momentum

v is the velocity

We have

$m = \frac{630}{7} \\$

We have the final answer as

Hope this helps you

5 0

3 years ago

Consider the following three statements: For any electromagnetic radiation, the product of the wavelength and the frequency is a

boyakko [2]

Answer:

The correct answer is B. Statements (i) and (ii) are true.

Explanation:

<u>Fisrt statement:</u>

Electromagnetic radiation such as wave, wavelength λ and oscillation frequency ν are related by a constant, the speed of light. The equation is given by:

$c= \lambda \nu$

So the first statement is true.

<u>Second statement:</u>

$c=\lambda \nu\\c= 3.0 A \times 1.0\times 10^{18} Hz\\c= 3.0\times 10^{-10} m \times 1.0\times 10^{18} s^{-1}\\c=3\times 10^8 \frac{m}{s}$

The value of c in the vacuum is 3×10⁸ m/s. Hence, the second statement is true.

<u>Third statement:</u>

The speed of any electromagnetic radiation is constant regardless the type of radiation.

Hence, the third statement is false.

8 0

3 years ago

A ball at the end of a string is swinging in a horizontal circle of radius 0.85 m. The ball makes exactly 3 revolutions per seco

Anettt [7]

Answer:

It's centripetal acceleration is 301.7 m/s²

Explanation:

The formula to be used here is that of the centripetal acceleration which is

ac = rω²

where ac is the centripetal acceleration = ?

ω is the angular velocity = 3 revolutions per second is to be converted to radian per second: 3 × 2π = 3 × 2 × 3.14 = 18.84 rad/s

r is the radius = 0.85 m

ac = 0.85 × 18.84²

ac = 301.7 m/s²

It's centripetal acceleration is 301.7 m/s²

8 0

3 years ago