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3 years ago

Why do stars seem to move at night? ght

Physics

2 answers:

frez [133]3 years ago

5 0

Answer:

it because the earth rotates slowly on it's axis which causes day and night

Tema [17]3 years ago

4 0

It looks that way cause the earth is rotation on its axis

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A 10 kg box is 1.3 m above the ground. How much potential energy does it have? (g on Earth of 9.8 m/s?

Volgvan

Potential energy = mgh
Potential energy = 10 x 9.8 x 1.3
Potential energy = 127.4 J

8 0

3 years ago

a body weights 28N at a height of 3200km from the earth surface.What will be the gravitational force on that body if its lies on

alekssr [168]

Answer:

The object would weight 63 N on the Earth surface

Explanation:

We can use the general expression for the gravitational force between two objects to solve this problem, considering that in both cases, the mass of the Earth is the same. Notice as well that we know the gravitational force (weight) of the object at 3200 km from the Earth surface, which is (3200 + 6400 = 9600 km) from the center of the Earth:

$F_G=G\,\frac{M_E\,m}{d^2} \\28\,\,N=G\,\frac{M_E\,m}{9600000^2}$

Now, if the body is on the surface of the Earth, its weight (w) would be:

$F_G=G\,\frac{M_E\,m}{d^2} \\w=G\,\frac{M_E\,m}{6400000^2}$

Now we can divide term by term the two equations above, to cancel out common factors and end up with a simple proportion:

$\frac{w}{28} =\frac{9600000^2}{6400000^2} \\\frac{w}{28} =\frac{9}{4} \\\\ \\w=\frac{9\,*\,28}{4}\,\,\,N\\w=63\,\,N \\$

4 0

3 years ago

What happens to the movement of particles in a liquid when it is heated?

Yanka [14]

Answer:

When heat is added to a substance, the molecules and atoms vibrate faster. As atoms vibrate faster, the space between atoms increases. The motion and spacing of the particles determines the state of matter of the substance. The end result of increased molecular motion is that the object expands and takes up more space.

Explanation:

3 0

3 years ago

Read 2 more answers

A lead bar 12 cm long, 2 cm wide, and 2 cm talk has a density of 11.3g/cm3. If you cut the bar in half, what is the density of o

VMariaS [17]

Answer:

The density of one halves 11.3 g / cm cube

Explanation:

Density remain same because cutting the bar in half , mass and volume will decrease to half so density will not change .

density = $\frac{mass}{volume}$

5 0

3 years ago

How is aperture measured? What do the measurements mean?

gulaghasi [49]

Aperture is measured in F-stops, in which the f-stops is the amount of light allowed to pass through the aperture, which simply put means that the smaller the aperture, the higher the f-stops. What it does is reduce the amount of light that reaches the film, so the higher the f-stops, the less light reaches the film.

4 0

3 years ago