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3 years ago

Three out of four crashes happen at a speed of __________ miles per hour or less.

1 answer:

5 0

<span>The answer is 45 miles per hour or even less. Most crashes occur at a speed of 45 miles per hour or even less, and most of these accidents occur close to our homes. These crashes may also be caused by different factors, such as being drunk or sudden occurrences that are not controllable, which is why it is best to precede with caution when driving at crowded areas.</span>

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A positive point charge q1 = +5.00 × 10−4C is held at a fixed position. A small object with mass 4.00×10−3kg and charge q2 = −3.

Lelechka [254]

Answer:

Therefore the speed of q₂ is 1961.19 m/s when it is 0.200 m from from q₁.

Explanation:

Energy conservation law: In isolated system the amount of total energy remains constant.

The types of energy are

Kinetic energy.
Potential energy.

Kinetic energy $=\frac{1}{2} mv^2$

Potential energy = $\frac{Kq_1q_2}{d}$

Here, q₁= +5.00×10⁻⁴C

q₂=-3.00×10⁻⁴C

d= distance = 4.00 m

V = velocity = 800 m/s

Total energy(E) =Kinetic energy+Potential energy

$=\frac{1}{2} mv^2$ + $\frac{Kq_1q_2}{d}$

$=\frac{1}{2} \times 4.00\times 10^{-3}\times(800)^2 +\frac{9\times10^9\times 5\times10^{-4}\times(-3\times10^{-4})}{4}$

=(1280-337.5)J

=942.5 J

Total energy of a system remains constant.

Therefore,

E $=\frac{1}{2} mv^2$ + $\frac{Kq_1q_2}{d}$

$\Rightarrow 942.5 = \frac{1}{2} \times 4 \times10^{-3} \times V^2 +\frac{9\times10^{9}\times5\times 10^{-4}\times(-3\times 10^{-4})}{0.2}$

$\Rightarrow 942.5 = 2\times10^{-3}v^2 -6750$

$\Rightarrow 2 \times10^{-3}\times v^2= 942.5+6750$

$\Rightarrow v^2 = \frac{7692.5}{2\times 10^{-3}}$

$\Rightarrow v= 1961.19$ m/s

Therefore the speed of q₂ is 1961.19 m/s when it is 0.200 m from from q₁.

5 0

3 years ago

Why does the band of stability curve upward at high atomic numbers? excess neutrons are required due to the repulsion between th

ella [17]

The band of stability curves upward at high atomic numbers due to the fact that excess of neutrons are required due to the repulsion between protons.

Atomic number is the number of protons. As the number of protons (atomic number) increase, the electrical repulsion force, due to the same sign of the protons inside the nucleus, becomes more dominant compared to the nuclear force attractions, then the nucleus needs more neutrons to gain stability.The presence of more neutrons decrease the density of protons which decreases the repulsion among them.

3 0

3 years ago

PLEASE HELP ME! There are an estimated 200-400 billion stars in our galaxy, and possibly 100 billion galaxies in our universe. W

son4ous [18]

The answer to the question above is c hope this helps !!!!

8 0

3 years ago

Assuming that 70 percent of the Earth’s surface

Aneli [31]

We need to find the volume of a spherical shell with a radius of
6.37 million meters and a thickness of 0.95 mile.

The technically correct way to do this is to find the volume of the
outside of the shell, then find the volume of the inside of the shell,
and subtract the inside volume from the outside volume. That's
the REAL way to do it.

But look. This 'shell' (the 0.95 mile of water) is only about 1530 meters thick,
on a sphere with a radius of 6.37 million meters. The depth of the water is like
0.024 percent of the radius ! There's not a whole lot of difference between the
sphere outside the water and the sphere inside it.

So I want to do this problem the easier way ... Let's say that the volume
of the water is going to be

(the surface area that it covers on the Earth)
   times
    (the thickness of the coating of water) .

The area of a sphere is 4 pi Radius² .
That's
   (4 pi) x (6.37 x 10⁶ m)²

   = (4 pi) x (40.58 x 10¹² m²)

We're only interested in 70% of the total surface area.

   = (0.7) x (4 pi) x (40.58 x 10¹²) m²

   =    3.57 x 10¹⁴ square meters of Earth's surface.

The volume of the water covering that area is

   (the area) times (average depth of 0.95 mile) .

We have to change that 0.95 mile to meters.
The question reminds us that    1 mile = 1609 meters .
So the volume of the water is

      (the area) times (0.95 x 1609 meters).

But we're not there yet. The question isn't asking for the volume.
It's asking for the mass of the water.
We're ready to get the volume in cubic meters.
We're supposed to know that each cubic meter is 1,000 liters,
   and the mass of 1 liter of water is 1 kilogram.
So each cubic meter of volume is 1,000 kilograms of mass.

Now we're ready to dump all the numbers into the machine and
turn the crank. The mass of all this water will be

   (the surface area) x (0.95 x 1609 meters) x (1,000 kg/m³)

= (3.57 x 10¹⁴ m²) x   (1528.6 m) x (1,000 kg/m³)

= 5.457 x 10²⁰ kilograms .

This is my answer, and I'm stickin to it.

But ... just like all the other problems you get in high school, the
answer doesn't matter. The teacher doesn't need the answer,
and YOU don't need the answer. The reason you got this problem
for an assignment is to give you practice in HOW TO FIND the
answer ... how to plan what you're going to do with the problem,
and then how to carry it out.

I don't know how much effort you put into this problem, but somewhere
along the way, you chickened out and posted it on Brainly. So far, the
result of that decision was: The person who got all the practice was ME.
I got the good stuff, and all YOU got was the answer.

I hope my work is clear enough that you can go through it, and pick up
some of the good stuff for yourself.

3 0

3 years ago

Which statement best describes an atom? (2 points)

alekssr [168]

Answer:

A group of protons and neutrons that are surrounded by electrons I think that's the answer...

Explanation:

7 0

3 years ago

Read 2 more answers