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Stolb23 [73]
2 years ago
11

At what distance will a 80 W lightbulb have the same apparent brightness as a 120 W bulb viewed from a distance of 40 m

Physics
1 answer:
liq [111]2 years ago
4 0

Answer:

32.6mm

Explanation:

Using area of a sphere(bulb) = 4πr²

So A is proportional to radius²

So the Energy will be proportional to r²

But 120/80 = 1.5 is the energy factor so

Using

1.5/d² = 1/r²

1.5/40²= 1/r^2

r = √( 40²/ 1.5)

r = 32.6m

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If you stir the juice it increases the surface area.

8 0
2 years ago
A circus acrobat is shot out of a cannon with an initial upward speed of 34 ft/s. if the acrobat leaves the cannon 4 ft above th
jok3333 [9.3K]
<h2>It will take 0.125 seconds to reach the net.</h2>

Explanation:

Initial speed, u = 34 ft/s = 10.36 m/s

Acceleration, a = -9.81 m/s²

Displacement, s = Final height - Initial height = 8 - 4 = 4 ft = 1.22 m

We have equation of motion, s = ut + 0.5 at²

Substituting

              s = ut + 0.5 at²

              1.22 = 10.36 x t + 0.5 x -9.81 x t²

              4.905t² - 10.36 t + 1.22 = 0

              t = 1.99 s     or    t = 0.125 seconds

Minimum time is 0.125 seconds.

It will take 0.125 seconds to reach the net.

6 0
3 years ago
A baseball player throws a baseball at a speed of 40 meters per second at an angle of 30 degrees. What is the velocity of projec
Vesna [10]

Answer:

The horizontal component of the velocity is the cosine of 30 degrees multiplied by 40m/s. The cosine of 30 degrees is the 0.8660 . To get the speed, multiply by 40m/s. This equals 34.64, which is approximately 35m/s.

Hope it helpss :)

3 0
2 years ago
Read 2 more answers
A small 24 kilogram canoe is floating downriver at a speed of 2 m/s. What is the canoe's kinetic energy?
USPshnik [31]
J can get answer on this way:
Ek=m*V*V/2= (24kg*2m/s*2m/s)/2=48 Ј
3 0
3 years ago
An electroscope is a simple device consisting of a metal ball that is attached by a conductor to two thin leaves of metal foil p
baherus [9]

Answer:

the electroscope separate  by the presence of charge carriers

Explanation:

Metal bodies are characterized by having free (mobile) electrons. In the electroscope the plates are in balance; when the external metal ball is touched, a charge is introduced into the device, when the body that touched the ball is separated, an excess charge remains. This charge, being a metal, is distributed over the entire surface, giving a uniform density and an electric force of repulsion is created between the two charged sheets, which tends to separate the sheets. This force is counteracted by the tension component as the sheets are separated at a given angle, the separation reaches the point where

                  Fe - Tx = 0

                  Fe = Tx

In summary, the electroscope separate its leaves by the presence of charge carriers

3 0
2 years ago
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