Please help it’s multiple choice

The velocity of the rock just before it hits the ground is approximately 23.87m/s.

From the third equation of motion;

v² = u² + 2gs

Where u is initial velocity, v is final velocity, g is acceleration due to gravity ( g = 9.8m/s² ) and s is distance covered.

Given the data in the question;

To determine the final velocity, plug the given values into the equation of motion above.

v² = u² + 2gs

v² = ( 3.61m/s )² + ( 2 × 9.8m/s² × 28.4m )

v² = 13.0321m²/s² + 556.64m²/s²

v² = 569.6721m²/s²

v = √( 569.6721m²/s²)

v = 23.87m/s

Therefore, the final velocity of the object is 23.87m/s.

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Answer:

In the solar cells, the energy is obtained only during the day, when the Sun shines. .So, it increases the cost of using solar panels as the source of energy. So, the solar cell is not used to meet all our energy needs

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Explanation:

Answer:

In the solar cells, the energy is obtained only during the day, when the Sun shines. ... So, it increases the cost of using solar panels as the source of energy. So, the solar cell is not used to meet all our energy needs

Explanation:

n the solar cells, the solar panel convert solar energy into electricity, which is stored in storage battery. The storage battery give the direct current but all the appliances are working by the alternating current, so first of all direct current is converted into alternating current by any suitable appliances before it can be used to run various devices. So it increases the cost of using solar panels as the source of energy. 

Explanation:

The natural environment or natural world encompasses all living and non-living things occurring naturally, meaning in this case not artificial. The term is most often applied to the Earth or some parts of Earth

Answer:

C

Explanation:

a parallel circuit because there is more than one path

Answer:

C) a parallel circuit because there is more than one path

Explanation:

EDGE 2022

Answer:

Explanation:

This is true because the definition of work is the parallel force required to move an object times the distance it moves. If it doesn't move, no work has been done. That is not to say that no energy has been expended, because it most certainly has! But that is not the same thing.

Answer:

yes

Explanation:

Reactions of acids with metals

Acids react with most metals and, when they do, a salt is produced. But unlike the reaction between acids and bases, we do not get water. Instead we get hydrogen gas.

This is the general word equation for the reaction:

metal + acid → salt + hydrogen

For example, magnesium reacts with hydrochloric acid to produce magnesium chloride:

magnesium + hydrochloric acid → magnesium chloride + hydrogen

Mg + 2HCl → MgCl2 + H2

It doesn't matter which metal or which acid is used, if there is a reaction we always get hydrogen gas as well as the salt. However, how quickly the reaction goes depends on the metal used and how high up in the reactivity series it is.

Answer:

The net force is 785 N

Explanation:

The net force = Force in one direction - force in the opposite direction

Here the Downward force due to gravity = 1000N

and the Upward force of air = 215 N

The net force = Downward force due to gravity -Upward force of air

Substituting the given values, we get -

The net force = 1000 -215  = 785 N

Hence, the net force is 785 N

Answer:

I am in 8th grade, and I am learning this, and it is kinda hard, but I appreciate all these people helping people answer thee hard science problems

Answer:

When a ray of light, passes from a denser to a rarer medium with the angle of incidence greater than the critical angle, the ray is reflected back into the same medium. This phenomenon is call total internal reflection.

Answer:

a. Volts = current x resistance

Explanation:

Ohm's law states that at constant temperature, the current flowing in an electrical circuit is directly proportional to the voltage applied across the two points and inversely proportional to the resistance in the electrical circuit.

Mathematically, Ohm's law is given by the formula;

[tex] V = IR[/tex]

Where;

V represents voltage measured in voltage.

I represents current measured in amperes.

R represents resistance measured in ohms.

Hence, Ohm's law gives the relationship between voltage, current and resistance of an electric circuit.

Answer:

8.575 m

Explanation:

speed = distance/time

distance -- 2d

343 = 2d/0.05

2d = 17.15

d = 17.15/2

d = 8.575

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Answer:

Fossil fuels store energy from the sun as

Explanation:

Answer:1. High Intensity Interval Training

HIIT stands for High Intensity Interval Training. HIIT is essentially a type of exercise, be it cardio or resistance training. HIIT. alternates between periods of high intensity, and low intensity (or recovery

2. flexibility and muscular strength

3. true

4. d

5. c

Explanation:

Answer:

792J

Explanation:

Use the formula Force × Distance

With 110 newtons being the force and 7.2 meters being the distance

Which gives 792 and work us measured in joules therefore its joules

Work done is the dot product of force and displacement. The work done on the box to push across the surface for 7.2 m by applying a force of 110 N is 792 J.

Force is an external agent acting on a body tp change it from the state of motion or rest.  Force is a vector quantity thus, it is characterized by a magnitude and direction.

When force acting on a body results in displacement of the body, it is said to be work done on the body. The work done on the body is the product of force and displacement.

W = F d.

Given the force acting on the box = 110 N

 displacement d = 7.2 m

Work done w = 110 N × 7.2 m

                       = 792 J.

Therefore, the work done on the box is 792 J.

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Answer:

6, 3, 2, 5, 4, 1

Explanation:

Let's describe them from smallest to largest. In fact the size order is not exact as there are exceptions.

An asteroid is a rocky body which lies in the asteroid belt between Mars and Jupiter. They are typically quite small object. The largest asteroid Ceres has been reclassified as a dwarf planet.

A moon is typically a rocky body which is in orbit around a planet. Some moons such as our Moon are quite large and are typically bigger than asteroid. Some moons can actually be smaller than some asteroids.

A planet is a nearly spherical body which is in orbit around the Sun. Planets are larger than moons.

A star is what planets orbit around. It is the source of light and heat. Our Sun is a star which is many times bigger than all of the planets.

A solar system is a star and all of its planets, asteroids, comets and other bodies. It is significantly bigger than a star.

A galaxy, such as our Milky Way Galaxy, is a collection of solar systems orbiting around a central core. Most galaxies have a supermassive black hole at their centres.

Galaxies also form clusters which are large scale structures.

The universe is everything. It contains billions of galaxies.

Answer: [tex]40\ N/C[/tex]

Explanation:

Given

Magnitude of charge is [tex]q=0.5\ C[/tex]

Force experienced is [tex]F=20\ N[/tex]

Electric field intensity is the electrostatic force per unit charge

[tex]\therefore E=\dfrac{F}{q}\\\\\Rightarrow E=\dfrac{20}{0.50}\\\\\Rightarrow E=40\ N/C[/tex]

Thus, the electric field intensity is [tex]40\ N/C[/tex]

Answer:

the velocity is 0.45 m/s and it is moving in the opposite direction

or

-0.45 m/s

Explanation:

The law of conservation of momentum says that  initial momentum = final momentum

( mass x velocity of the dog ) = - (mass x velocity of the canoe)

(15 x 1.2) =- (40 x velocity of the canoe)

Velocity of the canoe = -(15 x 1.2) / 40 = -0.45 m/s

Answer:

no

Explanation:

Answer:

12. b

13. a

Explanation:

Answer:

physical attractiveness

Explanation:

[tex]\tt\red{See \; Your \: Answer!}[/tex]

Your answer was 0.67m...

Answer:

the answer is letter A im not sure

Answer:

tenis

Tenis applies to each of Newton's 3 Laws of Motion because with the first law if a tenis ball is at rest it will stay at rest unless acted on by an unbalanced force which would be playing tenis in which it would stay in motion. The second law applies since the acceleration at which it is hit times the mass equals the force it has. The third law applies since when hitting a tenis ball back and forth with racquets the reaction may be equal or opposite

Answer: 20

Explanation: Mass number is the number of neutrons plus the number of protons. 8 + 12 gives 20.

Mass number

Mass number is 20

Answer:

Some of the work done on the cart became the cart’s potential energy, and some of the work was converted into heat by friction.

Explanation:

Here, some fraction of the work done by the student on the cart is converted to the potential energy of the cart it gained at the height.

Work done is the measure of the effectiveness of the force on making some displacement. It is the dot product of force and displacement. Work done like force is a vector quantity and have magnitude and direction.

When a force applied on a body results in a displacement, then it is said to be work is done on the body. The work done is numerically equal to the energy needed to displace the object.

Here, the force applied on the cart of 100 Kg results in a work done on the cart by pulling it to height. Where the energy equivalent to the work done is stored in the form its potential energy.  The potential energy

p = mgh

Some fraction of work done is stored as this energy while the remaining probably lost into the surroundings.

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Answer:

four times the

Explanation:

...........

Answer:

60m/s

Explanation:

v=frequency ×wave length

v signifies the speed

The speed of a wave is the product of its frequency and wavelength. Hence the speed of the wave with a frequency of 20 Hz and 30 cm wavelength is 0.6 m/s.

Frequency of a wave is the number of wave cycles  produced at unit time. Thus it has the unit of s⁻¹ which is equivalent hertz Hz.

Wavelength of a wave is the distance it travels in a wave cycle or for a transverse wave the distance between two consecutive crests or troughs is called wavelength.

The relation between frequency v, wavelength [tex]\lambda[/tex] and speed of a wave c is written as below:

[tex]c = v \lambda[/tex]

By this expression it is clear that the speed of increases with frequecy and wavelength.

The frequency of the given vibrational source is 20 Hz and the wavelength is 3 cm or 0.03 m. Hence, the speed of the wave is calculates as follows:

c = 20 Hz × 0.3 m

  = 0.6 m/s.

Therefore, the speed of the wave is 0.6 m/s.

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