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densk [106]
3 years ago
7

A student who weighs 500 newtons climbed the stairs from the first floor to the third floor,15 meters above, in 20 seconds. How

much work did she do
Physics
2 answers:
Darina [25.2K]3 years ago
6 0

Answer:

Work = (500N)(15m)=7500J Power= (7500J)/(20s) =375 W

Hopefully this helps

Explanation:

igor_vitrenko [27]3 years ago
5 0
Well, the 20 seconds gives us enough information to actually calculate the power she has on her feet :)
Well, the work is 500*15=7500J, that is 7.5 kJ or about 18 calories (1 cal is 418J?) The power is that 7.5 kJ divided by 20 seconds: 375W. That's... OK, I suppose...
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All objects emit what radiation
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If an object is not at Absolute Zero, then it is
absorbing and radiating thermal (heat) energy.
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3 years ago
The moon Phobos orbits Mars
dlinn [17]

Answer:

The moon Phobos orbits Mars

(mass = 6.42 x 1023 kg) at a distance

of 9.38 x 106 m. What is its period of

orbit?

Explanation:

Answer: 27.9816 x 10^3 is the period of orbit

8 0
3 years ago
A hydrogen discharge lamp emits light with two prominent wavelengths: 656 nm (red) and 486 nm (blue). The light enters a flint-g
mezya [45]

Answer:

The angle between the red and blue light is 1.7°.

Explanation:

Given that,

Wavelength of red = 656 nm

Wavelength of blue = 486 nm

Angle = 37°

Suppose we need to find the angle between the red and blue light as it leaves the prism

n_{r}=1.572

n_{b}=1.587

We need to calculate the angle for red wavelength

Using Snell's law,

n_{r}\sin\theta_{i}=n_{a}\sin\theta_{r}

Put the value into the formula

1.572\sin37=1\times\sin\theta_{r}

\theta_{r}=\sin^{-1}(\dfrac{1.572\sin37}{1})

\theta_{r}=71.0^{\circ}

We need to calculate the angle for blue wavelength

Using Snell's law,

n_{b}\sin\theta_{i}=n_{a}\sin\theta_{b}

Put the value into the formula

1.587\sin37=1\times\sin\theta_{b}

\theta_{b}=\sin^{-1}(\dfrac{1.587\sin37}{1})

\theta_{b}=72.7^{\circ}

We need to calculate the angle between the red and blue light

Using formula of angle

\Delta \theta=\theta_{b}-\theta_{r}

Put the value into the formula

\Delta \theta=72.7-71.0

\Delta \theta=1.7^{\circ}

Hence, The angle between the red and blue light is 1.7°.

8 0
3 years ago
I need help it is about physics
VMariaS [17]

Answer:

a force

Explanation:

Because if we apply force then only an object can slow down, speed up or change direction

6 0
3 years ago
Read 2 more answers
A "590-W" electric heater is designed to operate from 120-V lines.
lukranit [14]

Answer:

a) 24.4 Ω

b) 4.92 A

c) 495.9 W

d)

c. It will be larger. The resistance will be smaller so the current drawn will increase, increasing the power.

Explanation:

b)

The formula for power is:

P = IV

where,

P = Power of heater = 590 W

V = Voltage it takes = 120 V

I = Current Drawn = ?

Therefore,

590 W = (I)(120 V)

I = 590 W/120 V

<u>I = 4.92 A</u>

<u></u>

a)

From Ohm's Law:

V = IR

R = V/I

Therefore,

R = 120 V/4.92 A

<u>R = 24.4 Ω</u>

<u></u>

c)

For constant resistance and 110 V the power becomes:

P = V²/R

Therefore,

P = (110 V)²/24.4 Ω

<u>P = 495.9 W</u>

<u></u>

d)

If the resistance decreases, it will increase the current according to Ohm's Law. As a result of increase in current the power shall increase according to formula (P = VI). Therefore, correct option is:

<u>c. It will be larger. The resistance will be smaller so the current drawn will increase, increasing the power.</u>

7 0
3 years ago
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