Help me please..

Suppose a car is moving in a straight line and steadily increases its
speed. It goes from 0 miles/hour to 15 miles/hour the first second and 15
miles/hour to 30 miles/hour the next second. What is the acceleration?

A)10 miles/hour/second

B) 15 miles/hour/second

C) 20 miles/hour/second

D)30 miles/hour/second

Answer: Kids learn about the types of electromagnetic waves in the science of physics ... Microwaves are useful in communication because they can penetrate clouds, ... These are the infrared waves that are used in your TV remote to change channels

Explanation:

[tex]{\mathfrak{\underline{\purple{\:\:\: Given:-\:\:\:}}}} \\ \\[/tex]

[tex]\:\:\:\:\bullet\:\:\:\sf{First \: penetrating \: length\:(s_{1}) = 3 \: cm}[/tex]

[tex]\\[/tex]

[tex]{\mathfrak{\underline{\purple{\:\:\:To \:Find:-\:\:\:}}}} \\ \\[/tex]

[tex]\:\:\:\:\bullet\:\:\:\sf{Left \: Penetration \: length \: before \: it \: comes \: to \: rest \:( s_{2} )}[/tex]

[tex]\\[/tex]

[tex]{\mathfrak{\underline{\purple{\:\:\: Calculation:-\:\:\:}}}} \\ \\[/tex]

[tex]\:\:\:\:\bullet\:\:\:\sf{Let \: Initial \: velocity = v\:m/s} \\\\[/tex]

[tex]\:\:\:\:\bullet\:\:\:\sf{Left \: velocity \: after \: s_{1} \: penetration = \dfrac{v}{2} \:m/s} \\\\ [/tex]

[tex]\:\:\:\:\bullet\:\:\:\sf{s_{1} = \dfrac{3}{100} = 0.03 \: m}[/tex]

[tex]\\[/tex]

☯ As we know that,

[tex]\\[/tex]

[tex]\dashrightarrow\:\: \sf{ {v}^{2} = {u}^{2} + 2as }[/tex]

[tex]\\[/tex]

[tex]\dashrightarrow\:\: \sf{ \bigg(\dfrac{v}{2} \bigg)^{2} = {v}^{2} + 2a s_{1}}[/tex]

[tex]\\[/tex]

[tex]\dashrightarrow\:\: \sf{ \dfrac{ {v}^{2} }{4} = {v}^{2} + 2 \times a \times 0.03 }[/tex]

[tex]\\[/tex]

[tex]\dashrightarrow\:\: \sf{ \dfrac{ {v}^{2} }{4} - {v}^{2} = 0.06 \times a }[/tex]

[tex]\\[/tex]

[tex]\dashrightarrow\:\: \sf{\dfrac{ - 3{v}^{2} }{4} = 0.06 \times a }[/tex]

[tex]\\[/tex]

[tex]\dashrightarrow\:\: \sf{a = \dfrac{ - 3 {v}^{2} }{4 \times 0.06} }[/tex]

[tex]\\[/tex]

[tex]\dashrightarrow\:\: \sf{ a = \dfrac{ - 25 {v}^{2} }{2}\:m/s^{2} ......(1) }[/tex]

[tex]\\[/tex]

[tex]\:\:\:\:\bullet\:\:\:\sf{ Initial\:velocity=v\:m/s} \\\\ [/tex]

[tex]\:\:\:\:\bullet\:\:\:\sf{ Final \: velocity = 0 \: m/s }[/tex]

[tex]\\[/tex]

[tex]\dashrightarrow\:\: \sf{ {v}^{2} = {u}^{2} + 2as}[/tex]

[tex]\\[/tex]

[tex]\dashrightarrow\:\: \sf{{0}^{2} = {v}^{2} + 2 \times \dfrac{ - 25 {v}^{2} }{2} \times s }[/tex]

[tex]\\[/tex]

[tex]\dashrightarrow\:\: \sf{ - {v}^{2} = - 25 {v}^{2} \times s }[/tex]

[tex]\\[/tex]

[tex]\dashrightarrow\:\: \sf{ s = \dfrac{ - {v}^{2} }{ - 25 {v}^{2} }}[/tex]

[tex]\\[/tex]

[tex]\dashrightarrow\:\: \sf{ s = \dfrac{1}{25} }[/tex]

[tex]\\[/tex]

[tex]\dashrightarrow\:\: \sf{ s = 0.04 \: m }[/tex]

[tex]\\[/tex]

☯ For left penetration (s₂)

[tex]\\[/tex]

[tex]\dashrightarrow\:\: \sf{s = s_{1} + s_{2} }[/tex]

[tex]\\[/tex]

[tex]\dashrightarrow\:\: \sf{ 0.04 = 0.03 + s_{2}}[/tex]

[tex]\\[/tex]

[tex]\dashrightarrow\:\: \sf{ s_{2} = 0.04 - 0.03 }[/tex]

[tex]\\[/tex]

[tex]\dashrightarrow\:\: \sf{s_{2} = 0.01 \: m = {\boxed{\sf{\purple{1 \: cm }}} }}[/tex]

[tex]\\[/tex]

[tex]\star\:\sf{Left \: penetration \: before \: it \: come \: to \: rest \: is \:{\bf{ 1 \: cm}}} \\ [/tex]

Answer:

W = 27468000 [N] or 27.47 [kN]

Explanation:

The weight of a body is defined as the product of mass by gravitational acceleration.

[tex]W = m*g[/tex]

where:

W = weight of the rocket with fuel [kg]

m = mass = 2800000 [kg]

g = gravity acceleration = 9.81 [m/s²]

Now we can solve:

[tex]W = 2800000*9.81\\W = 27468000 [N][/tex]

The power required by the car if a 1430 kg car speeds up from rest to 14.0 m/s in 7.00 s is 20020 Joules.

In science and engineering, power is the rate at which work is completed or energy is delivered. It can be expressed as the product of the work completed (W) or the energy transferred (E) divided by the time interval (t), or W/t.

A high-powered motor can complete a given amount of work quickly, or a low-powered motor can accomplish it slowly. Foot-pounds per minute, joules per second (or watts), and ergs per second are examples of units of power, which measure work (or energy) per unit of time.

Given:

A 1430 kg car speeds up from rest to 14.0 m/s in 7.00 s,

Calculate the acceleration and displacement as shown below,

[tex]v = u + at[/tex]

14 =  0 + a × 7

a = 2 m/s²

[tex]s = ut + 1/2at^2[/tex]

s = 0 + 1 / 2 × 2 × 7²

s = 49 m,

Calculate the power as shown below,

Power = 1430 × 2 × 49 / 7

Power = 20020 Joules

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Unclear/incomplete question. However, I inferred you need an explanation of the phenomenon of rainfall​.

Explanation:

Basically, the phenomenon of rainfall​ follows a natural cycle called the water cycle. What we call 'rainfall' occurs when water condensed (in liquid form) in the atmosphere is made to fall down on the ground as tiny droplets as a result of the forces of gravity.

The water cycle makes rainfall possible:

Answer:

all are true so d is right

Explanation:

Electromagnets use electrlcity and magnets is true.

Magnetic fields are strongest around the poles of a magnet is true.

The south pole of a magnet will repel the south pole of another magnet is true

and since all of them is true the answer is d all of the above

Answer:

Air vacuum.

Explanation:

Air may seem like nothing, but there are tons of molecules in it. Air takes up space. When Angelica inhales, the air rushes into into and escapes the cup. Since theres no air anymore, the cup collapses because thereis no more space in it. She removes the air from the cup and it creates a vacuum inside, sucking the sides of the cup in.

Answer:

yes

Explanation:

yes

Answer:

that's true

Explanation:

if the rough inclined plane was rough enough than it would be true

Answer:

1400 math quiz

Explanation:

40s n shorty's

Answer:

The answer is "1557 meters".

Explanation:

speed of sound in ([tex]\frac{m}{s}[/tex]) [tex]= 331.5 + 0.60 \ T^{\circ}\ C\\\\[/tex]

[tex]\to V = 331.5 + 0.6 \times 24 = 346 \frac{m}{s}\\\\\to t = 4.5 \ seconds \\\\\to S = vt = 346 \times 4.5 = 1557 \ meters[/tex]

Answer:

Fossil fuels release carbon dioxide into the atmosphere. Natural gas is the best fossil fuel in terms of energy output per unit of carbon dioxide emitted. Biomass is renewable because a new crop can be grown after each harvest, and biomass is a low carbon fuel. Biomass has the approximate chemical formula CHO.

Explanation:

Answer:

The value is  [tex]\mu_k = 0.102[/tex]

Explanation:

From the question we are told that

   The initial speed of the pluck is  [tex]u = 10 \ m/s[/tex]

    The  distance it slides on the horizontal ice is  [tex]s = 50 \ m[/tex]

Generally from kinematic equation we have that

       [tex]v^2 = u^2 + 2as[/tex]      

Here v is  is the final velocity and the value is 0 m/s given that the pluck came to rest, so

      [tex]0^2 = 10 ^2 + 2* a * 50[/tex]      

=>   [tex]a = - 1 \ m/s^2[/tex]

Here the negative sign show that the pluck is decelerating  

 Generally the force applied on the pluck is  equal to the frictional force experienced by the pluck

      So  

                [tex]F = F_f[/tex]

=>            [tex]m * a = m* g * \mu_k[/tex]

=>             [tex]1 = 9.8 * \mu_k[/tex]

=>              [tex]\mu_k = 0.102[/tex]

it would be the 3rd one. so C

Answer:

b) 1.4km

Explanation:

Answer:

a

  [tex]\lambda = 202.7 \ m[/tex]

b

  [tex]w = 9.3 *10^{6} \ rad/s[/tex]

c

  [tex]k = 0.031 m^{-1}[/tex]

d

  [tex]E_{max} = 9.0 *10^{-3} \ V/m[/tex]

Explanation:

From the question we are told that  

       The frequency of the radio station is  [tex]f= 1480 \ kHz = 1480 *10^{3}\ Hz[/tex]

         The magnitude of the magnetic field is  [tex]B = 3.0* 10^{-11} \ T[/tex]

Generally the wavelength is mathematically represented as

          [tex]\lambda = \frac{c}{f}[/tex]

Here c is the speed of light with value  [tex]c = 3.0 *10^{8} \ m/s[/tex]

So

        [tex]\lambda = \frac{3.0 *10^{8}}{ 1480 *10^{3}}[/tex]

=>      [tex]\lambda = 202.7 \ m[/tex]

Generally the angular frequency is mathematically represented as

       [tex]w = 2 \pi * f[/tex]

=>   [tex]w = 2 * 3.142 * 1480 *10^{3}[/tex]

=>   [tex]w = 9.3 *10^{6} \ rad/s[/tex]

Generally the wave number is mathematically represented as        

=>      [tex]k = \frac{2 \pi }{\lambda}[/tex]

=>      [tex]k = \frac{2 * 3.142 }{ 202.7}[/tex]

=>      [tex]k = 0.031 m^{-1}[/tex]

Generally the amplitude of the electric field at this distance from the transmitter is mathematically represented as

         [tex]E_{max} = c * B[/tex]

=>      [tex]E_{max} = 3.0 *10^{8} * 3.0* 10^{-11}[/tex]

=>      [tex]E_{max} = 9.0 *10^{-3} \ V/m[/tex]

Answer:

The speed Clyde will be falling at is 33.72.

Answer:

C

Explanation:

It cant be A or D, meaning your left with B and C. there cant be an answer in the 1000's place eather

The exercise involves filling in the gaps with the possible wave

properties that can be obtained from a spring.

The correctly completed exercise is presented as follows;

A wave is a disturbance that moves through a medium. There are two

types of waves. A mechanical wave requires matter to travel. List some

examples of this type: sound wave, water wave, spring waves.

A electromagnetic wave does not require a medium. Examples include: Light waves

In order to start and transmit a mechanical wave, a source of

disturbance and a physical medium are required. A single disturbance is

referred to as a pulse, and a series of disturbance is a wave train.

This type of wave is called transverse wave. Its pulses are called crest

and troughs.

Now send a pulse by quickly pushing the spring forward and pulling it

back, as shown. This type of wave is called longitudinal wave. Watch the

motion of the ribbon. In this type, the particles move parallel to the

direction the wave travels. Its pulses are called compression and

rarefactions. Note that all waves transfer energy without transferring

matter. In mechanical waves, particle of the medium vibrate back and

forth in simple harmonic motion while the disturbance (or energy)

moves from one place to another.

B. Wave speed

Does the pulse catch up to the other? yes. The size of the pulse is called

the amplitude of the wave.

Did the size of the pulse affect the speed? No.

The average time wave it takes the wave to travel

Without changing your positions therefore keeping the distance the

pulse travels the same), pull the slinky tighter using only about 3/4 of

coils. This makes a completely different medium through which the

pulse will travel. Time the journey as before time record. Does the kind

of medium affect the speed of the pulse? Yes

C. Wavelength and Frequency

High frequency waves have short wavelengths and low frequency waves

have long wavelengths.

The speed of a wave in any medium is equal to the frequency of the wave × the wavelength. This wave equation [tex]\underline{f = \dfrac{v}{\lambda } }[/tex] shows that f and λ are

inversely proportional. The units of the variables are;

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Given :

A copper plate of mass 3.0g.

Atomic number, z = 29.

Atomic mass, M.M = 63.5 g/mol.

Avogadro's number, [tex]N_a = 6.02\times 10^{23}\ atoms[/tex].

Charge on electron, [tex]e = 1.6\times 10^{-19}\ C[/tex].

To Find :

The total charge of all the electrons.

Solution :

Moles of copper,

[tex]m = \dfrac{3}{63.5}\ moles\\\\m = 0.047 \ moles[/tex]

Number of atoms in 0.047 moles of copper :

[tex]n = 0.047\times 6.02\times 10^{23}\\\\n = 2.83\times 10^{22} \ atoms[/tex]

Since, there are 29 electrons on each atoms.

So, total charge is :

[tex]C = 2.83\times 10^{22}\times 29\times 1.6\times 10^{-19}\ C\\\\C = 131312\ C\\\\C = 1.31 \times 10^5\ C[/tex]

Hence, this is the required solution.

Answer:

A) Z-1

Explanation:

when a radioactive element of atomic number Z emits an alpha particle, the mass of the new nucleus decreases by 2, i.e the new atomic number of the element = ( Z- 2).

Also, when the daughter nucleus emits a beta particle, the new nucleus increases by 1,  that is the new atomic number of the element = (Z + 1).

Thus, the atomic number of resulting nuclide = Z ( - 2) + ( + 1).

                                                                           = Z - 2 + 1

                                                                           = Z - 1

Therefore, the atomic number of resulting nuclide is Z - 1

Answer: Age

Explanation:

Physical fitness has to do with the effective and efficient working of the body system which allows individuals to be healthy.

The factors that are critical in developing good physical fitness include the environment, the behavior of the individual and heredity. To maintain physical fitness, one should exercise, eat healthy, avoid smoking etc. Age is not a factor in physical fitness.

Answer:

The current is 11 Amperes

Explanation:

Electric Current

The electric current is defined as a stream of charged particles that move through a conductive path.

The current intensity can be calculated as:

[tex]\displaystyle I=\frac{Q}{t}[/tex]

Where:

Q = Electric charge

t   = Time taken by the charge to move through the conductor

The current intensity is often measured in Amperes.

The charge passing through a point in a circuit is Q= 55 c during t=5 seconds, thus the current intensity is:

[tex]\displaystyle I=\frac{55}{5}[/tex]

I = 11 Amp

The current is 11 Amperes

Answer:

The disk covers a rotation of 90º after 3 seconds.

Explanation:

Since the disk rotates at constant angular speed, we can determine the change in angular position ([tex]\Delta \theta[/tex]), measured in sexagesimal degrees, by the following kinematic formula:

[tex]\Delta \theta = \omega\cdot \Delta t[/tex] (1)

Where:

[tex]\omega[/tex] - Angular velocity, measured in sexagesimal degrees per second.

[tex]\Delta t[/tex] - Time, measured in seconds.

If we know that [tex]\omega= 30\,\frac{\circ}{s}[/tex] and [tex]\Delta t = 3\,s[/tex], then the change in angular position is:

[tex]\Delta \theta = \left(30\,\frac{\circ}{s} \right)\cdot (3\,s)[/tex]

[tex]\Delta \theta = 90^{\circ}[/tex]

The disk covers a rotation of 90º after 3 seconds.

Answer:

-240

Explanation:

A motorcycle skids for a distance of 2.0 m on an icy road, then the change in kinetic energy for the motorcycle will be equal to -240 J.

The force which a moving object has is referred to as kinetic energy in physics. It is defined as the number of effort required to propel a person of a specific mass from still to a specific velocity.

Aside from slight fluctuations in speed, your body holds onto the kinetic energy it obtains during acceleration.

When the body slows down from its present level to a condition of rest, the same quantity of energy is used.

Formally, kinetic energy is any quantity that has a gradient concerning time in the Lagrangian of a system.

As per the given information in the question,

Distance, d = 2.0 m

Friction, f = 120 N

The angle between displacement and friction force, θ = 180°

Now, the change in kinetic energy for the motorcycle = Work done by the friction.

K.E = f × d(cos θ)

= 120 (2.0 m)(cos 180°)

Δ K.E = -240 J

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Answer:

12445 J

Explanation:

Given that

Power output, P = 5 kW

efficiency of the engine, e = 27% = 0.27

Thermal energy expelled, Q(c) = 9085 J

Heat absorbed, Q(h) = ?

Using the formula

e = W/Q(h)

e = [Q(h) - Q(c)] / Q(h)

e = 1 - Q(c)/Q(h)

Now, substituting the values into the formula, we have

0.27 = 1 - 9085/Q(h)

9085/Q(h) = 1 - 0.27

9085/Q(h) = 0.73

Q(h) = 9085 / 0.73

Q(h) = 12445 J

Thus, the heat absorbed is 12445 J

Answer:

Speed and direction.....