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3 years ago

5

Which astronomer proved that the planets of our solar system move in elliptical orbits? A. Kepler B. Copernicus C. Ptolemy D. Ga

lileo

2 answers:

daser333 [38]3 years ago

5 0

The answer is A) kelper

Ierofanga [76]3 years ago

3 0

The answer is Kepler

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A space probe produces a radio signal pulse. If the pulse reaches Earth 12.3 seconds after it is emitted by the probe, what is t

adoni [48]

Answer:

Distance = 3.69 × 10^9 m

The distance from the probe to Earth is 3.69 × 10^9 m

Explanation:

Distance from the probe to the Earth can be derived using the simple motion formula;

Distance = speed × time .....1

Since a radio signal uses an electromagnetic wave to transfer signal, it has the same speed as the speed of light.

Speed of radio signal = speed of light = 3.0 × 10^8 m/s

time taken to reach the earth = 12.3 seconds

Substituting the values of speed and time into equation 1;

Distance = 3.0 × 10^8 m/s × 12.3 s

Distance = 36.9 × 10^8 m

Distance = 3.69 × 10^9 m

Note: all electromagnetic radiation have the same speed which is equal to 3.0 × 10^8 m/s

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2 years ago

The earth's radius is about 4000 miles. kampala, the capital of uganda, and singapore are both nearly on the equator. the distan

Y_Kistochka [10]

<span>The solution is: Earth circumference is 2*pi*r=25,130 miles 25,130 miles corresponds to 360Âş, so 5,000 miles corresponds to 360*5000/25130 = 71,6Âş 71,6Âş is equivalent to 71,6*2pi/360=1,25 radians Angular velocity is 1,25/9=0,139 rad/h</span>

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3 years ago

Thiết bị trao đổi nhiệt ngược chiều, nhiệt độ chất lỏng nóng vào là 310°C, ra là 115°c. Nhiệt độ chất lỏng lạnh vào là 25°c và r

Vika [28.1K]

Answer: 129.5 m

Explanation:

310 + 115 + 25 + 68 = 518

518 / 4 = 129.5 m

i think. Sorry if this is wrong

:)

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3 years ago

Which subatomic particle has the smallest mass?

spin [16.1K]

Answer:

quark

Explanation:

neutrón= 1.675 x 10-27 kg

proton=1,673 x 10-27 kg

electron=9,11 x 10-31 kg

quark=7,13 - 14,26 · 10−30 kg

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1 year ago

A 100 kg box sits on an incline held at rest by a very thin rope attached to another mass hanging as shown. The force of frictio

MAVERICK [17]

If friction is acting along the plane upwards

then in this case we will have

For equilibrium of 100 kg box on inclined plane we have

$mgsin\theta = F_f + T$

also for other side of hanging mass we have

$T = Mg = 50(9.8) = 490 N$

now we have

$100(9.8)sin\theta = 100 + 490$

$980sin\theta = 590$

$sin\theta = 0.602$

$\theta = 37 degree$

In other case we can assume that friction will act along the plane downwards

so now in that case we will have

$mgsin\theta + F_f = T$

also we have

$T = Mg = 50(9.8) N$

now we have

$100(9.8)sin\theta + 100 = 50(9.8)$

$980sin\theta + 100 = 490$

$980 sin\theta = 490 - 100$

$sin\theta = 0.397$

$\theta = 23.45 degree$

<em>So the range of angle will be 23.45 degree to 37 degree</em>

6 0

3 years ago