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2 years ago

The illuminance due to a 60.0-w lightbulb at 3.0m is 9.35 lx. What is the total luminous flux of the bulb

1 answer:

3 0

The equation for luminous flux is given as P = 4 $\pi$ $r^{2}$ E
where P is the luminous flux, r is the distance and E is the illumination. The unit for P is lumen, E is lux and r is in meters. Substituting the given to the equation:

P = 4 $\pi$ $r^{2}$ E

P= 4 $\pi$ $(3)^{2}$ (9.35) = 1057.46 lumens (lm)

The total luminous flux is equal to 1057.46 lumens (lm).

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Galileo’s pendulum theory stated that the time taken to swing through one complete cycle of a pendulum depends on what?

Amanda [17]

Answer: it depends on the mass of the pendulum or on the size of the arc through which it swings.

Explanation:

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2 years ago

If a steady-state heat transfer rate of 3 kW is conducted through a section of insulating material 1.0 m2 in cross section and 2

kaheart [24]

Answer:

$\Delta T = \frac{3000 W *0.025 m}{1 m^2 (0.2 \frac{W}{mK})}= 375 K$

So then the difference of temperature across the material would be $\Delta T = 375 K$

Explanation:

For this case we can use the Fourier Law of heat conduction given by the following equation:

$Q = -kA \frac{\Delta T}{\Delta x}$ (1)

Where k = thermal conductivity = 0.2 W/ mK

A= 1m^2 represent the cross sectional area

Q= 3KW represent the rate of heat transfer

$\Delta T$ is the temperature of difference that we want to find

$\Delta x=2.5 cm =0.025 m$ represent the thickness of the material

If we solve $\Delta T$ in absolute value from the equation (1) we got:

$\Delta T =\frac{Q \Delta x}{Ak}$

First we convert 3KW to W and we got:

$Q= 3 KW* \frac{1000W}{1 Kw}= 3000 W$

And we have everything to replace and we got:

$\Delta T = \frac{3000 W *0.025 m}{1 m^2 (0.2 \frac{W}{mK})}= 375 K$

So then the difference of temperature across the material would be $\Delta T = 375 K$

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3 years ago

Why does a heavier object fall faster

Salsk061 [2.6K]

Explanation:

In a vacuum (no air resistance), it doesn't. All falling objects, regardless of mass, accelerate at the same rate.

However, when air resistance is taken into account, heavier objects indeed fall faster than lighter objects, provided they have the same shape and size. For example, a lead ball falls faster than a styrofoam ball.

To understand why, first look at what factors affect air resistance:

D = ½ρv²CA

where ρ is air density,

v is velocity,

C is drag coefficient,

and A is cross sectional area.

As falling objects accelerate, they eventually reach a maximum velocity where air resistance equals weight. This is called terminal velocity.

D = W

½ρv²CA = mg

v = √(2mg/(ρCA))

If we increase m while holding everything else constant, v increases. So two objects with the same size and shape but different masses will have different terminal velocities, with the heavier object falling faster.

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2 years ago

Read 2 more answers

Which of the following is true about a combustion reaction?

Ksenya-84 [330]

Answer:

Explanation:

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2 years ago

Processes such as dissolving, melting, freezing, and evaporationg can affect the appearance of a substance, but the identity of

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