I know that the answer is 20, but I don’t know if it’s B or D. Please help

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Answer:

Polonium Marked as Po with atomic number 84, is a highly radioactive heavy metal. It is arguably the most lethal known material.

Explanation:

Answer:

B.

Explanation:

w=mg

g=10m/s

hope this helps

true North is fixed point on the globe

magnetic North is the direction that a compass needle points to as it aligns with the earths magnetic field and what is interesting is that the magnetic North pole shifts and changes over time in response to change in the earth's magnetic core

Answer:

kinetic energy is needed for potential energy since without kinetic energy potential energy would not have the potential energy to do anything

sorry if it doesn't make sense

Explanation:

youre holding a ball in the sky that is potential energy since it has the potential to fall. the kinetic energy is when it falls and lastly the potential is when it hits the floor..

Answer:

The acceleration of the sled is 1.584 m/s².

Explanation:

Friction always occur when two surfaces slide across one another. For example, if we push an object and it starts moving, we can say there's a kinect (dynamic) friction force between that object and the surface under.

Now, let's solve the problem.

First, we've got to write the data down.

[tex]\bullet \quad m=300\,kg\\\\\bullet \quad F=828\,N\\\\\bullet \quad \mu_k=0.120[/tex]

Sketch a picture of the problem and point all forces acting on the sled (see attached).

Apply Newton's Second Law Of Motion:

[tex]F_{net}=m\cdot a[/tex]

Let's set our reference system positive to the right. Above equation becomes:

[tex]F-f_k=m\cdot a[/tex]

where [tex]f_k[/tex] is the kinect friction force.

Looking up free body diagram, we can see support force equals the weight of the sled, so that we can write:

[tex]F-\mu_k\cdot m \cdot g=m \cdot a[/tex]

Solving for a:

[tex]a=\dfrac{F-\mu_k \cdot m \cdot g}{m}[/tex]

Let's take 9.8 m/s² for the acceleration of gravity and plug the data on the equation.

[tex]a=\dfrac{828-(0.120)\cdot 300\cdot(9.8)}{300}[/tex]

[tex]\therefore \boxed{a=1.584\,m/s^2}[/tex]

Conclusion: the acceleration of the sled is 1.584 m/s².

Keep learning with this link:

Friction force

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Brainly Team

This question involves the concepts of centripetal force, range of projectile and projectile motion.

The magnitude of centripetal force is "2812.8 N".

First, we will find the velocity of the ball by using the formula of the range of the projectile.

[tex]R = \frac{v^2Sin2\theta}{g}[/tex]

where,

R = range of projectile = 86.75 m

v = speed = ?

θ = launch angle = 47.9°

g = acceleration due to gravity = 9.81 m/s²

Therefore,

[tex]86.75\ m = \frac{(v)^2Sin(2)(47.9^o)}{9.81\ m/s^2}\\\\v = \sqrt{\frac{(86.75\ m)(9.81\ m/s^2)}{Sin95.8^o}}[/tex]

v = 29.25 m/s

Now, we will use the formula to find out the centripetal force:

[tex]F_c = \frac{mv^2}{r}[/tex]

where,

[tex]F_c[/tex] = Centripetal Force = ?

m = mass of the ball = 7.3 kg

v = speed = 29.25 m/s

r = radius = 2.22 m

Therefore,

[tex]F_c = \frac{(7.3\ kg)(29.25\ m/s)^2}{2.22\ m}[/tex]

Fc = 2812.8 N = 2.812 KN

Learn more about centripetal force here:

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Answer:

469

Explanation:

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Answer:

5.978 años luz

Explanation:

Hi! Your answer is: The distance between the Barnard's star and Earth is 5.978 light years.

Answer: There would be 20 electrons.

Explanation: Remember the electrons number is the same as the atomic number.

Explanation:

13 protons are in the nucleus of an aluminum atom

Explanation:

At first it is in 14m position but position doesn't matter in displacement, similar case for time taken.

So at first it travels 6m in positive direction.

So displacement= 6m

Then it travels 13 in opposite or negative direction.

So displacement = 6 -13 m = -7 m

Hope it helps ya

You're standing in the lobby of a huge building.

You go up 6 floors.

You stop and catch your breath.

You go down 13 floors.

Where do you end up ?

The combination of a particle's mass and velocity produces momentum. Momentum is a vector quantity that has both magnitude and direction. The force exerted on a particle is equated to the time rate of change of momentum by Isaac Newton's second equation of motion.

First law of Newton : According to Newton's first law of motion, if a body is at rest or moving in a straight path at a constant speed, it will stay in that state or continue to move in that direction unless it is acted upon by an outside force.

Second law of Newton : According to Newton's second rule of motion, a body's rate of momentum change is inversely proportional to the force acting on it, and momentum changes occur in the direction of the net applied force.

Third law of Newton : Newton's third law of motion states that there is always an equal and opposite reaction to every action.

In order to accomplish work and to produce heat and light, energy must be transferred to a body or to a physical system. Energy is the quantitative attribute that does this.

A push or pull that an object experiences as a result of its interactions with its environment is known as a force.

Dust and smoke rising in the atmosphere as a result of an asteroid impact hinder sunlight from reaching our planet, resulting in a decrease in global temperature. Many living beings could die as a result of this incident. A small city might be destroyed if an asteroid the size of an apartment strikes Earth. A 20-story building-sized asteroid might wipe out a small nation if it were to strike Earth.

To get more information about Newton's Laws of motion :

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Answer:

122.5 meters

Explanation:

We have the third equation of motion:

[tex]\boxed{\mathsf{v^2=u^2+2aS}}[/tex]

Here, the particle is a flare.

It's initial velocity is 49 m/ s and the final will be zero, that's 'cause the particle comes to a standstill upon reaching its maximum, in case of motion under gravity.

a will be the acceleration due to gravity = 9.8 m/ s²

So, here are the terms we've got for the third eqn. of motion:

Now, the term we've got to find out is the height reached by the flare, i. e., S.

=> v² = u² + 2aS

=> (0)² = (49)² + 2×(-9.8)×S

=> 0 = 49×49 - 2×9.8×S

=> 2×9.8×S = 49×49

[tex]\implies \mathsf{S=\frac{49\times 49}{2\times9.8} }[/tex]

=> S = [tex]\frac{245}{2}[/tex]

And, S is the maximum height the flare covers, so the answer is 122. 5 meters

Answer:

The question is missing something it doesn't say how fast down its going and doesn't show the figure sorry for wasting an answer

Answer:

The force formula is defined by Newton's second law of motion: Force exerted by an object equals mass times acceleration of that object: F = m×a( force = mass×area)

Answer:

A.protons and neutrons in the nucleus.

The speed of the ball when it returns to the same horizontal level is 8 m/s.

The given parameters;

During the motion of a projectile, the speed of the projectile reduces as the projectile moves upwards and eventually becomes zero at the maximum height.

As the projectile moves downwards, the speed of the projectile starts to increase and it will become maximum (equal to the initial speed) before the projectile hits the ground.

Thus, we can conclude that the speed of the ball when it returns to the same horizontal level is 8 m/s.

Learn more here:https://brainly.com/question/16272865

Answer:

plz mark me brianliest I really want it (puppy eyes) plzzzzzz

Explanation:

Like olfactory cells that detect odors, auditory receptor cells (also called hair cells) are recessed from the surface of the body. ... Sound waves are converted into vibrations in a fluid in the inner ear, and these vibrations indirectly move the hair cells, which then send electrical signals to the brain.

From the information provided, the velocity after 2 seconds is  11 m/s.

From the equations of motion;

v = u + at

Where;

v = final velocity

a = acceleration

t = time taken

The initial velocity of the bike was 7 m/s and its acceleration is  2 m/s2. This change occurred within a time of 2 seconds.

Hence;

v = 7 + 2(2)

v = 11 m/s

The velocity after 2 seconds is  11 m/s.

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Answer:

its B

Explanation:

It's B & A at the same time because A. a roller coaster uses brakes to slow down and stop. B is the most reasonable answer. Because all roller coasters go up and over a second time over the hill, but they also slow down. But go with B.

TELL ME IF I´M RITE

Speed, distance and time can be calculated using a magic triangle. D (the distance) goes in the top of the triangle, S (speed) goes in the bottom left of the triangle and T (time) goes in the bottom right of the triangle.

Answer:

B. contains substance s that are not mixed in a specific ratio

Explanation:

the proportion of constituents in a mixture can vary

Answer:

the free body diagram models the forces acting on an object. The object or 'body' is usually shown as a box or a dot. The forces are shown as thin arrows pointing away from the centre of the box or dot. ... It is important to label each arrow to show the magnitude of the force it represents.

Answer:

There are only 38 points.

Explanation:

why are you saying 75?

Answer:

100 m/s ÷ 8 = 12.5 m/s

Explanation:

You must put multiply (÷)