Help me please I’ll give brainliest

Answer:

6.8 m/s

Explanation:

To solve this, we would use the Doppler's Effect. Doppler's effect is represented by the formula

f = [(g + vr)/(g + vs)].fo, where

f = observed frequency, 408 Hz

g = speed of sound in air, 340 m/s

vr = velocity of the receiver

vs = velocity of the source, 0 m/s

fo = source frequency, 400 Hz

Now, applying the values to the equation, we have

408 = [(340 + vr)/(340 + 0) * 400

408/400 = (340 + vr)/340

1.02 * 340 = 340 + vr

346.8 = 340 + vr

vr = 346.8 - 340

vr = 6.8 m/s

Therefore the speed at which the boy is riding his bicycle towards the wall is 6.8 m/s

Just flip one of the batteries to connect one's positive terminal to others negative terminal.

Answer:

The room become bright in the day by a process call scattering of light or Rayleigh scattering.

Explanation:

It is called Rayleigh scattering or scattering of light because Rayleigh scattering is the scattering if light or electromagnetic radiation by smaller particles which have radius of less than 110 nanometer in a medium and the wavelengths of the electromagnetic. Wave or light remain unchanged. The scattering of light occur in the day time in the room and this bring of brighten up of the room.

Answer:

see below

Explanation:

alluminium is,

1.lustrous

2.highly malleable

3.reactive metal

4.some times acts as non metal

5.good conductor

6.obtained from bauxite

7.Atomic number 13 so electrons and protons are 13

8.neurons are 14

9.ductile

10.melting point is very high approximately 660 degree celsius.

Answer:

It has low density, is non-toxic, has a high thermal conductivity, has excellent corrosion resistance and can be easily cast, machined and formed.

Explanation:

Answer:

By using [tex]v^{2}_{f} = v^{2}_{i} + 2a\Delta y[/tex], with [tex]v_{i} = -12m/s[/tex] and [tex]\Delta y = -40m[/tex]:

[tex]v^{2}_{f} = v^{2}_{i} + 2a/Delta y[/tex]

[tex]v^{2} = (-12m/s)^{2} + 2(-9.80m/s^{2})(-40m)[/tex]

[tex]v = -30m/s[/tex]

Explanation:

Hope this helped!

A rock is thrown downward from the top of a 40 m tall tower, with The speed of the rock just before hitting the ground will be equal to -30 m/s.

Friction is the resistance to a thing moving or rolling over another solid object. Although frictional forces can be advantageous, such as the traction required to walk while slipping, they also provide a significant amount of resistance to motion. In order to overcome frictional resistance in the moving parts, about 20% of an automobile's engine power is used.

The forces of attraction, also referred to as adhesion, between the contact zones of the surface, which are always minutely uneven, seem to be the main contributor to friction between metals.

From the given information in the question,

v²(f) = v²(i) + 2aΔy

v² = (-12 m/s)² + 2(-9.8)(-40)

v = -30 m/s.

Therefore, the velocity of the rock is -30 m/s.

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Answer:

(A)

Explanation:

Answer:

275 x 10"N

Explanation:

Answer: 67 how much candy does nick have

Explanation:

Answer:

2.01

Explanation:

First, we need to find the centripetal acceleration.

We're given that the merry go round rotates 1 revolution in 2.09 seconds. Converting to rpm, we know that it rotates 30 revolution per minute

Now this speed gotten in rpm will be converted to m/s, to ease the calculation

30 rpm = πdN/60 m/s

30 rpm = (3.142 * 4 * 30)/60

30 rpm = 377.04/60

30 rpm = 6.284 m/s

a(c) = v²/r

a(c) = 6.284²/2

a(c) = 39.49 / 2

a(c) = 19.74 m/s²

F = ma

F = 50 * 19.74

F = 987 N

Also, Normal Force, F(n) =

F(n) = mg

F(n) = 50 * 9.81

F(n) = 490.5

We then use this to find the coefficient of static friction, μ

μ = F/F(n)

μ = 987 / 490.5

μ = 2.01

Answer:

2.51 kg * m/s

Explanation:

In order to find momentum, use the equation below:

momentum = mass * velocity.

Since neither mass nor velocity was given, you must solve for both variables.

In order to solve for mass, use the force equation for its weight / gravitational force.

Fg (gravitational force) = 3.2 N = ma = 9.8m

mass = 3.2 N / 9.8 m/s^2 = 0.326531 kg

In order to solve for velocity, use the equation:

velocity = displacement / time

velocity = 10m / 1.3 s = 7.69231 m/s

Momentum = mass * velocity = 0.326531 kg *  7.69231 m/s = 2.51177 kg * m/s = 2.51 kg * m/s

Answer:

330

Explanation:

(a) The torque the net thrust produces about the center of the circle is of 20 N-m.

(b) The angular acceleration of the airplane when it is in this horizontal flight is 0.1 rad/s².

Given data:

The mass of model airplane is, m = 1.0 kg.

The radius of horizontal circle is, r = 20.0 m.

The magnitude of net thrust by engine is, F = 1.0 N.

(a)

The effort made to turn any object is known as the torque. The mathematical expression for the torque is given as,

T = F × r

Solving as,

T = 1.0 × 20.0

T = 20 N-m

Thus, we can conclude that the torque the net thrust produces about the center of the circle is of 20 N-m.

(b)

The expression for the angular acceleration of airplane during the horizontal flight is given as,

[tex]T = I \times \alpha[/tex]

Here, I is the moment of inertia of airplane and its value is,

[tex]I = \dfrac{1}{2}mr^{2}\\\\\\I = \dfrac{1}{2} \times 1.0 \times 20^{2}\\\\\\I =200 \;\rm kg.m^{2}[/tex]

So, the angular acceleration is,

20 = 200 × α

α = 20/200

α = 0.1 rad/s²

Thus, we can conclude that the angular acceleration of the airplane when it is in this horizontal flight is 0.1 rad/s².

Learn more about the torque here:

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Answer: no because you have left the number

Explanation:

Answer:

The answer is "0.5555 m"

Explanation:

Where the reference leaves the list and the viewer is at rest:

[tex]\lambda'=\frac{v-v_s}{v} \times \lambda\\\\[/tex]

   [tex]=\frac{343 \frac{m}{s} - (-62.4 \frac{m}{s})}{343 \frac{m}{s}} \times 0.47 \ m\\\\ =\frac{343 \frac{m}{s} + 62.4 \frac{m}{s}}{343 \frac{m}{s}} \times 0.47 \ m\\\\ =\frac{405.4 \frac{m}{s}}{343 \frac{m}{s}} \times 0.47 \ m\\\\ =\frac{405.4 \frac{m}{s}}{343 \frac{m}{s}} \times 0.47 \ m[/tex]

   [tex]=0.5555 \ m[/tex]

Answer:

true

Explanation:

Hello!!

For the maximum height the final velocity is zero, because can't up more.

Then, use the formula:

V = Vi + gt

Replacing, we have:

0 m/s = 5,3 m/s + (-9,8 m/s² * t)

0 m/s - 5,3 m/s = -9,8 m/s² * t

(-5,3 m/s) / -9,8 m/s² = t

t = 0,54 s

The time it will take to reach the maximum height is 0,54 seconds.

Answer:

0.00129rad/s

Explanation:

The angular velocity is expressed as;

v = wr

w is the angular velocity

r is the radius

Given

v =  20,000 mph

r = 4300mi

Get w;

w = v/r

w = 20000* 0.44704/4300*1609.34

w = 8940.8/6,920,162

w = 0.00129rad/s

Hence the angular velocity generated is 0.00129rad/s

Answer:

Explanation:

Basically you just have to find the left vectors. To do so divide A, C and D into horizontal and vertical vector. A: 10km to south and 10root3 to east. Just sine and cosine of 30 at 20km. D: 15 km to west and 15root3 to south. Again sine and cosine of 60 at 30 km. C: 45 degrees so 20root2 to north and east. Add all these up with B. Then you have 7.696 km due south and 19.395 km due west. Resultant displacement magnitude = root(7.696^2+19.395^2)=20.866 south of west with angle=arctan(7.696/19.395)=21.644 degrees

Answer:

Since binary is only 1 and 0, you can use a flashlight to display something similar to Morse code (see explanation below)

Explanation:

In binary, 1 means "on" and 0 means "off". A way you can use visible light is through turning on and off a flashlight. If the flashlight is turned on, it would represent a 1. If the flashlight is turned off, it would represent a 0. To make the message easier and more accurately understood for the receiver make sure to flash the lights in a consistent pattern (ex. each flash lasts no longer than half a second, one second between each digit, etc.)

For example, let's say you're trying to send the message "11001"

  on     on    off     off     on

0       1       2       3       4       5      Numbers represent seconds

As you can see above the message starts at 0 seconds. Between 0 and 1 seconds the flashlight is turned on once. Between 1 and 2 seconds the flashlight is turned on again, Between 2 and 3 seconds as well as 3 and 4 seconds the flashlight is not turned on at all. And finally between 4 and 5 seconds the flashlight is turned on.

They could determine it by counting their total amount of miles mark went by the directions he went to walk those miles.

Answer:

27.95[kW*min]

Explanation:

We must remember that the power can be determined by the product of the current by the voltage.

[tex]P=V*I[/tex]

where:

P = power [W]

V = voltage [volt]

I = amperage [Amp]

Now replacing:

[tex]P=110*8.47\\P=931.7[W][/tex]

Now the energy consumed can be obtained mediate the multiplication of the power by the amount of time in operation, we must obtain an amount in Kw per hour [kW-min]

[tex]Energy = 931.7[kW]*30[days]*10[\frac{min}{1day} ]=279510[W*min]or 27.95[kW*min][/tex]

Answer: The height of the cliff is 104.59 m

Explanation:

The horizontal speed of the car when it leaves the cliff is 13 m/s, and it hits the ground 60m from the shoreline.

Here we can use the relationship:

Time*Speed = Distance.

To find the time that the car is in the air, we know that:

speed = 13m/s

distance = 60m

time = T

13m/s*T = 60m

T = (60m)/13m/s = 4.62 s

This means that the car is falling for 4.62 seconds.

Now let's analyze the vertical problem.

As the car leaves the cliff, it only has horizontal velocity, this means that the vertical initial velocity will be zero

The only force acting in the vertical axis is the gravitational force, this means that the acceleration will be equal to the gravitational acceleration, which is:

g = 9.8m/s^2

then:

a = -9.8m/s^2

Where the negative sign is because the acceleration is pulling the car downwards.

To get the vertical velocity, we could integrate over time to get:

v(t) = (-9.8m/s^2)*t + v0

Where v0 is the constant of integration and the initial vertical velocity, that we already know that is equal to zero, then the vertical velocity as a function of time can be written as:

v(t) = (-9.8m/s^2)*t

To get the vertical position equation, we need to integrate again over the time:

P(t) = (1/2)*(-9.8m/s^2)*t^2 + H

Where H is the constant of integration and the initial vertical position, then H will be the height of the cliff.

We know that the car needs 4.62 seconds to hit the ground, this means that:

P(4.6s) = 0m

Then:

P(t) = (1/2)*(-9.8m/s^2)*(4.62s)^2 + H = 0

            (-4.9m/s^2)*(4.62s)^2 + H = 0

          H =  (4.9m/s^2)*(4.62s)^2 = 104.59 m

This means that the cliff is 104.59 meters high

Answer:

The frequency stays the same and the wavelength decreases.

Explanation:

When sound wave enters a new medium where sound travels faster, its frequency will remain same because it depends only on the source.

The relation between wavelength and speed is inverse, it means when the speed of sound increases, its wavelength will decrease.

So, the frequency stays the same and the wavelength decreases. Hence, the correct option is (d).

Answer:

yo can someone answer i need this

Explanation:

Answer:

Dark matter:

- Doesn't interact with baryonic matter.

- It has not been observed directly

- dark matter does not absorb, reflect or even emit light, thereby making it to be extremely hard to spot. Therefore, it does not interact with electromagnetic radiation.

Explanation:

Dark matter:

- Doesn't interact with baryonic matter.

- It has not been observed directly

- dark matter does not absorb, reflect or even emit light, thereby making it to be extremely hard to spot. Therefore, it does not interact with electromagnetic radiation.

Baryonic matter:

- Has been observed directly because it includes nearly all the matter that we see in the world daily.

- It interacts with baryonic matter

- interacts with electromagnetic radiation

Dark Matter:

Baryonic Matter:

Dark matter can be defined as often invisible substances that are difficult to spot because they don't absorb, emit or reflect light.

Hence, dark matter do not affect human view because they do not interact or interfere with electromagnetic radiation (force).

Although, humans can see right through the (weakly interacting) dark matter but it has not been observed directly.

Baryonic matter can be defined as a dark matter that is made up of baryons such as neutrons, and protons. Also, they are ordinary matter (both fermions and hadrons), as distinct from exotic forms.

In conclusion. baryonic matter has been observed directly and it can interact with electromagnetic radiation.

Read more: https://brainly.com/question/15677526

Answer:

angle of reflection and angle of incident is always equal

Answer:

See the answers and the explanation below.

Explanation:

To solve these questions we must understand that speed is the relationship between the displacement and the time that the displacement lasts.

1. 300 [km], in 5 [hr]

d = displacement [km]

[tex]v = d/t[/tex]

where:

v = velocity [km/h]

t = time [hr]

[tex]v = 300/5\\v = 60 [km/h][/tex]

In one hour : [tex]d = 60*1\\d = 60 [km][/tex]

b. Car B 100 [km] in 2 [hr]

[tex]v =100/2\\v = 50 [km/h]\\[/tex]

C. The car A has the greatest average speed.

Answer:

The value is [tex]s =197.88 \ m[/tex]  

Explanation:

From the question we are told that

    The  impulse is  [tex]I = 950 \ N\cdot s[/tex]

    The mass is  [tex]m = 12 \ kg[/tex]

     The time t =  5 s

Generally impulse is mathematically represented as

         [tex]I = F * t[/tex]

=>       [tex]F = \frac{I}{t}[/tex]

=>       [tex]F = \frac{950 }{ 5 }[/tex]

=>       [tex]F = 190 \ N[/tex]

Generally force is mathematically represented as

      [tex]F = m * a[/tex]

=>    [tex]a = \frac{F }{ m }[/tex]

=>     [tex]a = \frac{190 }{ 12 }[/tex]

=>     [tex]a = 15.83 \ m/s^2[/tex]

Generally from kinematic equation , the distance covered is  

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

Here  u is the initial velocity of the cart and the value is [tex]u = m/s[/tex]

=>   [tex]s = 0 * 5 + \frac{1}{2} * 15.83 * 5^2[/tex]  

=>   [tex]s =197.88 \ m[/tex]  

Answer:

The second one I think

Explanation:

B

Answer:

0.159

Explanation:

Given that

F1 = 440 N

F2 = 340 N

m = 500 kg

acceleration, a = 0 m/s²

Remember that F = m.a

If F - f(f) = 0, then F = f(f)

N = mg

f(f) = μN, substituting for N, we have

f(f) = μmg

The total force, F = F1 + F2

F = 440 + 340

F = 780 N

Recall that we'd already proven that

F = f(f), so F = 780 N = f(f)

And again, f(f) = μmg, if we substitute for all the values, we have

780 = μ * 500 * 9.81

780 = μ * 4905

μ = 780 / 4905

μ = 0.159

Therefore, the coefficient of static friction of the crate on the floor is 0.159

Answer:

0.8 m/s

Explanation:

F(avg) * Δt = I, where

F(avg) = Average force

Δt = change in time

I = impulse

From the question, we know that the

average force is given as -17600 N

time change is given as 55 milliseconds

speed of the player, v = 8 m/s

Mass of the player is given as 110 kg

Impulse, I = F(avg) * Δt

I = -17600 * 0.055

I = -968

Now, using the Impulse-Momentum theory, we have that

Δp = I and thus,

Δp = m [v(f) - v(i)], where

Δp = change in the momentum

v(f) = final speed of the player

v(i) = initial speed of the player

Substituting the values, we have

I = m [v(f) - v(i)]

-968 = m.v(f) - m.v(i)

m.v(f) = m.v(i) - 968

110v(f) = 110 * 8 - 968

110v(f) = 880 - 968

110v(f) = -88

v(f) = -88 / 110

v(f) = -0.8 m/s