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Stolb23 [73]
3 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]3 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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Briefly explain the two postulates of relativity, how they differed from classical physics, and why Einstein was led to propose
Ray Of Light [21]

Explanation:

The two postulates of special theory of relativity

Postulate 1: The law of physics are invariant under any of inertial frame of reference.

Postulate 2: The velocity of light is remains same in each ans every frame of reference and independent of relativity.

They are differ from classical mechanics that in classical mechanics there is no change in mass and length in relative velocity but in relativistic mechanics it changes.

These two postulates implements in phenomenon like time dilation , length contraction etc.

Thanks

3 0
3 years ago
A flea jumps straight up to a maximum height of 0.550 m . what is its initial velocity v0 as it leaves the ground?
Alexxx [7]
Since my givens are x = .550m [Vsub0] = unknown
 [Asubx] = =9.80
 
 [Vsubx]^2 = [Vsub0x]^2 + 2[Asubx] * (X-[Xsub0]

[Vsubx]^2 = [Vsub0x]^2 + 2[Asubx] * (X-[Xsub0]) 

Vsubx is the final velocity, which at the max height is 0, and Xsub0 is just 0 as that's where it starts so I just plug the rest in

0^2 = [Vsub0x]^2 + 2[-9.80]*(.550)

0 = [Vsub0x]^2 -10.78

10.78 = [Vsub0x]^2

Sqrt(10.78) = 3.28 m/s 


3 0
3 years ago
How does the hydraulic garage lift helps to lift heavy weights?Explain in you words don't copy (write in the easiest way you cou
Sergeeva-Olga [200]

Answer:

this the way that hydraulic pump works:

The system of hydraulic jack lifts the heavy objects by transferring the oil from one chamber to another.

Through the suction valves into the two cylinders which creates pressure distributing the fluid equally to the points causing the objects to lift up.

hope these points helped u

any confusion then comment it

5 0
2 years ago
1.) What statement best explains the type of population growth seen in Belize according to the 2010 age structure diagram?
Art [367]

Answer:

1. Belize has a high birth rate and a low death rate.

2. Belize will have a rapidly growing population over the next twenty years.

Explanation:

Belize has a high birth rate and a low death rate. Belize is in the phase II of the demographic transition model. Their population is growing exponentially. This is due to lowering death rates while the birth rates are still high.

Belize will have a rapidly growing population over the next twenty years. When the age structure diagram has a wider base than the middle or top age groups, this indicates a population that is rapidly growing. Belize is early in the transition model and still has high birth rates. Countries like Belize typically have lower opportunities for education for women of reproductive age, can have high infant mortality, and can have high emigration rates.

7 0
3 years ago
At temperatures above roughly 800 °c, calcium carbonate will decompose. write and balance the equation for this reaction. phase
Lady_Fox [76]
CaCO3 ---->  CaO +  CO2 

hope it helps!

8 0
3 years ago
Read 2 more answers
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