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kakasveta [241]

2 years ago

9

How would the cost of operating a 30 watt bulb relate to the cost of operating a 60 watt bulb for a given amount of time?

1 answer:

never [62]2 years ago

6 0

Utility companies charge based on consumption in kWh. Range of approximately 3 to 10 cents per kWh (rates vary by locale)

So consumption is directly proportional to watts of the load.

A 30 watt light bulb running for 100 hrs
would cost half of what a 60 watt bulb burning for the same time frame.

30 x 100= 3 KWh

60 x 100= 6 kWh

So use LED lights that give same lumens for much less watts of power

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The pulley system below uses a gasoline engine to raise a drill head up through a smooth drill pipe. The engine provides a const

polet [3.4K]

NB: The diagram of the pulley system is not shown but the information provided is sufficient to answer the question

Answer:

Power = 2702.56 W

Explanation:

Let the power consumed be P

Energy expended = E = mgh

height, h = 5 m

E = 80 * 9.8 * 5

E = 3920 J

$Power = \frac{Energy}{time}$

To calculate the time, t

From F = ma

F = 900 N

900 = 80 a

a = 900/80

a = 11.25 m/s²

From the equation of motion, $s = ut + 0.5at^{2}$

The drill head starts from rest, u = 0 m/s

$5 = 0 * t + (0.5*11.25*t^{2} )\\5 = 5.625t^{2}\\t^{2} = 5/5.625\\t^{2} = 0.889\\t = 0.943 s$

Power, P = E/t

P = 3920/0.0.943

P = 4157.79 W

But Efficiency, E = 0.65

P = 0.65 * 4157.79

Power = 2702.56 W

6 0

2 years ago

Scientists have discovered just over _____ different elements with unique properties.

Y_Kistochka [10]

100. (: hope this helps

8 0

2 years ago

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a concrete slab 20 m long and weighing 400,000 N is supported by one pillar. A 19,600 N car is parked 8 meters from one end, whe

Elden [556K]

let the distance of pillar is "r" from one end of the slab

So here net torque must be balance with respect to pillar to be in balanced state

So here we will have

$Mg(r - L/2) = mg(L/2 - 8)$

here we know that

mg = 19600 N

Mg = 400,000 N

L = 20 m

from above equation we have

$400,000(r - 10) = 19,600 (10 - 8)$

$r - 10 = 0.098$

$r = 10.098 m$

so pillar is at distance 10.098 m from one end of the slab

3 0

2 years ago

Jasper made a list of the properties of electromagnetic waves. Identify the mistake in the list. Electromagnetic Wave Properties

Nata [24]

Answer:

Statement 2 is wrong

Explanation:

To check the statements in this exercise, let's describe the main properties of electromagnetic waves. Let's describe the characteristics

* they are transverse waves

* formed by the oscillations of the electric and magnetic fields

* the speed of the wave is the speed of light

with these concepts let's review the final statements

1) True. Formed by the oscillation of the two fields

2) False. They are transverse waves

3) True. Can travel by vacuum as they are supported by oscillations of the electric and magnetic fields

4) True. They all have the same speed of light

Statement 2 is wrong

6 0

2 years ago

Is this statement true or false? Electric currents flow easily through materials that are conductors and through materials that

Alex777 [14]

False because currents do not flow easily through insulators. If it only said conductors, then it would be true.

3 0

2 years ago

Read 2 more answers