A rock is dropped from a cliff 80m above the ground. How long does it take to reach the ground ?

Answer:

constant velocity

Answer: ummm is this a question?

Explanation: what I said up there ^

Answer:

8 million miles

Explanation:

believe me

20 degrees.

Sound travels faster when the medium (something to travel through) is less dense.

For example, Air is less dense than water, water is less dense than a solid.

In this case, since we are working with water, the colder the temperature of water, the denser it is. Likewise, the hotter the temperature of water, it gets less denser.

If this helped, please mark branliest.

The sound travels slowest through 20 degree temperature of water. The correct option is a.

A sound wave is a result of compression and rarefaction, by which sound is propagated in a material medium such as air.

Sound travels faster when the medium is less dense. In case of air, which is less dense than water.

When the temperature is increased, the object becomes less dense than previous state of the object. The sound wave travels faster in rarer medium than the denser medium.

So, sound travels slowest through 20 degree temperature of water.

Thus, the correct option is a.

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Given :

Mass of person, m = 60 kg.

Height of roof of building, h = 74.8 m .

To Find :

How much gravitational potential energy does she have at the top of the building.

Solution :

We know, gravitational potential energy is given by :

[tex]P.E = mgh[/tex]

Here, g = acceleration due to gravity = 9.8 m/s².

P.E = 60×9.8×74.8 J

P.E = 43982.4 J

P.E = 44 kJ

Hence, this is the required solution.

Answer:

Explanation:

because as the light shines through the glass, The glass reflects the light from different places in the glass causing the light to bend

Answer: If light enters any substance with a higher refractive index  it slows down. The light bends towards the normal line. If light travels enters into a substance with a lower refractive index it speeds up. The light bends away from the normal line.

Answer:

Explanation:

Initially, the plastic bottle lies sideways on the floor of a stationary bus, so the bottle is also in the stationary state.

When the bus starts moving, the bottle will try to maintain its state of rest as described by Newton's first law, due to which the bottle will slide in the backward direction and at the same time there is frictional force acting on the bottle in the forward direction by the bus floor due to which the speed of bottle starts increasing in the direction of the bus as described by Newton's second law.

After some time, the bus, as well as the bottle will move at the same constant speed as there is an application of frictional force.

On the sudden application of the break, the bus will reach the stationary position, but in order to maintain the inertia, the bottle will slide forward on the bus floor due to the inertia of the bottle as described by Newton's first law and at the same time there is frictional force acting on the bottle in the backward direction by the bus floor due to which the speed of bottle starts decreasing as described by Newton's second law.

Answer:

P=F/A

Explanation:

P. Is pressure

F is force

A is area

Answer:

Graph A is the Answer

Answer:

475861.044 is the wavelength

Explanation:

wavelength= speed/frequency

speed of light equals 299,792,458

and the frqeuncy equals 630

so  299,792,458/630=475861.044 equals the wavelength

The wavelength of the waves is equal to 476.2 m

The frequency of a wave can be described as the number of oscillations in one second. The frequency has S.I. units represented as per second or hertz.

Wavelength is the distance between the two adjacent points in phase with each other. Two adjacent crests or troughs are separated by a distance of a single wavelength.

The relationship between frequency, speed of the wave, and wavelength are:

c = νλ

Given, the frequency of the wave, ν = 630 kHz = 630 ×10³  s⁻¹

Then the speed of all electromagnetic waves including radio waves is equal to the speed of light, c = 3 ×10¹⁰ m/sc

The wavelength of the waves can be determined from the relationship:

λ = c/ν = 3× 10⁸/ 630 ×10³

λ = 476.2 m

Therefore, the wavelength of the wave is 476.2 m.

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Answer:

If the fired bullet leaves the gun muzzle parallel to the ground (no vertical y velocity), then it will only have horizontal (x direction) velocity, and the downward force of gravity will be the only vertical y force on the bullet. Hence the time it takes to strike the ground is the same as that of a dropped bullet.

Explanation:

Answer:

b

Explanation:

it is

An example of a transverse wave is; Choice D; the movement of a spring in a pogo stick

A transverse wave is a wave whose oscillations are perpendicular (at right-angle) to the direction of the wave's advance.

String waves are an example of transverse waves because the string moves up and down at right angles to the horizontal motion of the wave.

Read more on transverse waves;

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Answer:

25.56 m

Explanation:

For vertical movement , initial velocity u = 0

Displacement  h = 2 m

time taken = t

h = ut + 1/2 gt²

2 = .5 x 9.8 x t²

t² = .4081

t = .639 s

During this period , the ball will move in horizontal direction uniformly with velocity 40 m /s .

horizontal displacement = horizontal velocity x time

= 40 x .639 = 25.56 m

Answer:

negative

Explanation:

Answer:

a = 0.857143 m/s2

Explanation:

a=f/m

60/70

Answer:

The value is [tex]t = 5.124 \ s[/tex]

Explanation:

From the question we are told that

   The height of the tree is [tex]s = 20 \ m[/tex]

    The angle the ball leaves is  [tex]\theta = 45^o[/tex]

    The initial velocity  is  [tex]u = 30.0 \ m/s[/tex]

Generally the vertical of the ball's initial velocity is mathematically evaluated as

      [tex]u_y = u * sin (45)[/tex]

=>   [tex]u_y =- 30 * sin (45)[/tex]

=>   [tex]u_y = -21.21 \ m/s[/tex]

Here  [tex]u_y[/tex] is negative because it is in the direction of the negative y-axis

Generally from kinematic equation we have

      [tex]s = u_yt + \frac{1}{2} g t^2[/tex]

=>   [tex]20= -21.21 t +4.9 t^2[/tex]

=>   [tex]4.9 t^2 -21.21 t- 20= 0[/tex]

Solving using quadratic formula we have that

        [tex]t = 5.124 \ s[/tex]

Answer:

Hydrogen

Explanation: hopefully.

Answer:

final velocity 'v' = 71m/s distance 's' = 1000m intial velocity 'u' =0 therefore,using third equation of motion v^2- u^2=2*a*s 71*71=2*a*1000 a=71*71/(2*1000 a= 2.52m/s^2

Explanation:

Answer:

It is correct

Explanation:

N is a unit of force

m for distance

and kg for mass

dimension of force is MLT-2

dimension of distance is L

dimension of mass is M

then. Nm2kg-2 must be equal to [MLT-2][L2][M-2]

or, Nm2kg-2 = [M-1 L3 T-2]. --------1

force (F) = G (m1 x m2)/d2

or G = Fd2/(m1m2)

G = (MLT-2 . L2)/M-2

= M-1L3T-2. -----------2

EQN 1 = EQN 2

so given unit is correct

Answer: the correct answer is 8 please let me know if I’m wrong

Explanation:

Answer:

I’m not sure bro

Explanation:

Answer:

The whole country is in a very seismic area,and they have the densest seismic network in the world, so they are able to record many earthquakes. The spares seismic instrumentation in those areas doesn't allow us to actually record all the smaller earthquakes.

huh I dont understand your question.

One factor that affects the amount of friction is roughness or smoothness of the sliding object.

There are several factors affecting the amount of friction and they include the following;

Thus, one factor that affects the amount of friction is roughness or smoothness of the sliding object.

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Answer: It depends on the surface is the surface bumpy? Or is the surface flat and smooth?

Explanation: If a surface is to bumpy friction slows it down, if a surface is flat and smooth it glides with ease.

Answer:

The ideal temperature of catalase activity is 66.6 degrees Celsius, so a temperature between 60 degrees and 70 degrees should most likely release the most oxygen during the reaction.

Explanation:

Answer:

A satellite.

Explanation:

I got this answer right.

The satellite was the first launched craft during the Space Race. The correct answer would be an option (B)

The space race was a series of technological tests between the United States and the Soviet Union in order to demonstrate dominance in spaceflight. According to an online exhibit from the National Air and Space Museum, it was an offshoot of the mid-twentieth-century Cold War, a violent worldwide war that pitted the philosophies of capitalism and communism against one another (opens in new tab).

The first goal of this "space race" was to launch an unmanned object, a satellite, into orbit around the Earth.

A satellite is an instrument that has been sent into orbit to collect data or to serve as part of a communication system.

Thus, the correct answer would be option (B) satellite was the first launched craft during the Space Race.

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Answer:

Explanation:

Given parameters:

Initial velocity  = 8.5m/s

Acceleration  = 4.1m/s²

Time  = 2.7s

Unknown:

Distance downhill traveled  = ?

Solution:

To solve this problem, we have to adopt the right motion equation;

          S = ut + [tex]\frac{1}{2}[/tex]at²

where  s = distance

            u = initial velocity

            a = acceleration

            t = time taken

Insert the parameters and solve;

  S = (8.5 x 2.7) + ([tex]\frac{1}{2}[/tex] x 4.1 x 2.7²)

  S = 22.95 + 14.95

  S = 37.9m

The acceleration necessary to keep the object in uniform circular motion is 43.48 m/s²

From the question given above, the following data were obtained:

The acceleration required to keep the object in circula motion can be obtained as follow:

a = v² / r

a = 10² / 2.3

a = 100 / 2.3

a = 43.48 m/s²

Thus, the acceleration required to keep the object in circula motion is 43.48 m/s².

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Answer:

The correct option is C

Explanation:

From the question we are told that

  The speed of the ball in the horizontal direction is  [tex]v = 40 m/s[/tex]

   The height from which the ball is thrown is s =  2 m

Generally from kinematic equation

     [tex]s = ut + \frac{1}{2} gt^2[/tex]

Here u is the initial  velocity of the ball and this zero  given that the ball was at rest before it was thrown.

So

    [tex]2 = 0 * t + \frac{1}{2} 9.8t^2[/tex]

=>  [tex]t = 0.6889 \ s[/tex]

Generally the distance the ball will travel before touching the ground is  

      [tex]d = v * t[/tex]

=>    [tex]d = 40 * 0.6389[/tex]

=>    [tex]d = 25.56 \ m[/tex]

Responder:

100m

Explicación:

Dirección total de la persona de recogida hacia el este = 300 m + 100 m (ya que caminó 100 m hacia el este cuando el conductor lo llamó)

Dirección total de la persona de recogida a través del este = 400 m

Para el súper conductor, fue 800 m hacia el este y regresa por (800-300) m cuando vio que había pasado a la persona de recogida por 300 m. El desplazamiento total del uber es 800-300 = 500 m

El desplazamiento total del uber a la persona que recoge es la diferencia en su desplazamiento, es decir, 500-400 = 100 m.