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1 year ago

50 J of work was performed in 20 seconds. How much power was used to do this task?

Physics

2 answers:

Cloud [144]1 year ago

8 0

The Correct answer to this question for Penn Foster Students is: 2.5 W

yuradex [85]1 year ago

7 0

Power=work/time
power=50/20
50/20=2.5
Therefore A. 2.5 W

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A person on a cruise ship is doing laps on the promenade deck. on one portion of the track the person is moving north with a spe

Dmitry [639]

The resultant motion is given by pithagoras, since the two components (north and east) are perpendicular to each other.
They are asking you about the direction so you have to use trigonometry, finding that the direction is Ф=arctan(3.8/12)=17.57° north of east.

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2 years ago

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A transmission channel is made up of three sections. The first section introduces a loss of 16dB, the second an amplification (o

AlekseyPX

Answer:

$P_{out} = 0.100 W = 100 mW$

Explanation:

The attached image shows the system expressed in the question.

We can define an expression for the system.

The equivalent equation for the system would be

$G_{total} = G_{1} + G_{2} + G_{3}\\G_{total} = -16dB+20dB-10 dB = -6 dB$

so, the input signal could be expressed in dB terms

$P_{in} [dB] = 10 log_{10}(P_{in}) \\P_{in} [dB] = 10 log_{10}(0.4)\\P_{in} [dB] = -3.97 dB$ (1)

so the output signal could be expressed as.

$P_{out} = P_{in} + G_{1} + G_{2} + G_{3}\\P_{out} = -3.97 dB - 6dB = -9.97 dB$

The gain should be expressed in dB terms and power in dBm terms so

$P_{out} = -9.97 + 30 = 20.03 dBm$

using the (1) equation to find it in terms of Watts

$P_{out} = 0.100 W = 100 mW$

3 0

2 years ago

I take 1.0 kg of ice and dump it into 1.0 kg of water and, when equilibrium is reached, I have 2.0 kg of ice at 0°C. The water w

VashaNatasha [74]

Answer:

.c. −160°C

Explanation:

In the whole process one kg of water at 0°C loses heat to form one kg of ice and heat lost by them is taken up by ice at −160°C . Now see whether heat lost is equal to heat gained or not.

heat lost by 1 kg of water at 0°C

= mass x latent heat

= 1 x 80000 cals

= 80000 cals

heat gained by ice at −160°C to form ice at 0°C

= mass x specific heat of ice x rise in temperature

= 1 x .5 x 1000 x 160

= 80000 cals

so , heat lost = heat gained.

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2 years ago

At what distance above earth would a satellite have a period of 125 min?

Nezavi [6.7K]

Rw^2 = GmM/r^2
 Leads to
 w^2 r^3 = GM
 (2pi /T) ^2 r^3 = GM
 4pi^2 r^3 = GM T^2
 r^3 = GM T^2 / 4pi^2
 Work out r^3 then r.
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 R = 6.38E6 m
 m = 5.97E24 kg
 G = 6.673E-11
 r= 8279791.78 m
Since r = radius R of Earth + height above urface,h
 h = r - R = 8279791.78 - 6.38E6 = 1899791.78 m
h= 1899.79178 Km

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2 years ago

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13. An aircraft heads North at 320 km/h rel:

AURORKA [14]

The velocity of the aircraft relative to the ground is 240 km/h North

Explanation:

We can solve this problem by using vector addition. In fact, the velocity of the aircraft relative to the ground is the (vector) sum between the velocity of the aircraft relative to the air and the velocity of the air relative to the ground.

Mathematically:

$v' = v + v_a$