There is a theory that gravity could pull galaxies back together, causing a reverse big bang.

How do we live on earth if the earth is in the sky?

PtichkaEL [24]

Answer:

We live on earth because we are not floating in the sky.

Explanation:

Because earth may be in the sky but we are not technically we are in the sky on earth not in the sky that's incorrect.

4 0

2 years ago

Two identical point charges in outer space are held apart at a distance D. As soon as the charges are released, each begins movi

AVprozaik [17]

Answer:

B. 4a

Explanation:

Force between the charges is inversely proportional to the square of the distance

=> Force will be 4 times and acceleration will be 4a

=> Answer b).

6 0

3 years ago

Read 2 more answers

How do you find weight =mass×gravitational acceleration

Artist 52 [7]

That's a formula that shows the relationship between three quantities ...
weight, mass, and acceleration. If you know any two of them, then you
can use this formula to find the one you don't know.

Examples:

==> I have a rock with 2 kilograms of mass.
The gravitational acceleration on Earth is 9.8 m/s² .
How much does my rock weigh on Earth ?

   Weight = (mass) x (grav acceleration)
      = (2 kg) x (9.8 m/s²)
   = 19.6 newtons
      (about 4.41 pounds)

==> My brother weighs 770 newtons (about 173 pounds) on Earth.
   What is his mass ?

       Weight = (mass) x (grav acceleration)

   770 newtons = (mass) x (9.8 m/s²)
Divide each side
by 9.8 m/s²:    770 newtons / 9.8 m/s² = mass

    78.57 kilograms = mass

==> When I went to the Moon, I took along my 2-kilogram rock.
   I weighed my rock on the Moon.
   It weighs 3.25 newtons (about 0.73 pound) there.
   What is the gravitational acceleration on the Moon ?

   Weight = (mass) x (grav acceleration)

   3.25 newtons = (2 kg) x (acceleration)

Divide each side
by 2 kilograms: (3.25 newtons)/(2 kg) = acceleration

    1.63 m/s² = grav acceleration on the Moon

7 0

3 years ago

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Two identical isolated conducting spheres are picked for an experiment. Only one of them is charged. If the spheres are now brie

aev [14]

Because they are conducting, when you bring them together the charge is split equally among the two spheres (because they have the same radius the amount of charge is also equal). Now they will repel each other because of the net charge on each with the same polarity.

5 0

3 years ago

The following questions present a twist on the scenario above to test your understanding. Suppose another stone is thrown horizo

Ipatiy [6.2K]

The first part of the text is missing, you can find on google:

"A ball is thrown horizontally from the roof of a building 45 m. If it strikes the ground 56 m away, find the following values."

Let's now solve the different parts.

(a) 3.03 s

The time of flight can be found by analyzing the vertical motion only. The vertical displacement at time t is given by

$y(t) = h -\frac{1}{2}gt^2$

where

h = 45 m is the initial height

g = 9.8 m/s^2 is the acceleration of gravity

When y=0, the ball reaches the ground, so the time taken for this to happen can be found by substituting y=0 and solving for the time:

$0=h-\frac{1}{2}gt^2\\t=\sqrt{\frac{2h}{g}}=\sqrt{\frac{2(45)}{9.8}}=3.03 s$

(b) 18.5 m/s

For this part, we need to analyze the horizontal motion only, which is a uniform motion at constant speed.

The horizontal position is given by

$x=v_x t$

where

$v_x$ is the horizontal speed, which is constant

t is the time

At t = 3.03 s (time of flight), we know that the horizontal position is x = 56 m. By substituting these numbers and solving for vx, we find the horizontal speed:

$v_x = \frac{x}{t}=\frac{56}{3.03}=18.5 m/s$