How are radar and an approaching siren alike? How are they different?

A. Both use sound waves, but the Doppler effect can be observed
only with radar.

B. Both use sound waves, but the Doppler effect can be observed
only in the approaching siren.

C. Both exhibit the Doppler effect, but radar uses radio, and the siren
'uses sound waves.

D. Both exhibit the Doppler effect, but radar uses sound waves, and
the siren uses radio.

As you were holding the block down and in place, the spring exerted an upward force that balanced the downward push by your hand and its own weight. So this restoring force has a magnitude of R such that

R - 50 N - (3 kg) g = 0   =>   R = 79.4 N

As soon as you remove your hand, the block has acceleration a such that, by Newton's second law,

R - (3 kg) g = (3 kg) a   =>   a = (79.4 N - (3 kg) g) / (3 kg) ≈ 16.7 m/s^2

pointing upward.

Answer: 588 N

Explanation: pressure = force/area, or p = F/A. Then p1=p2

And F1//A1 = F2/A2 . F2 = F1·A2/A1 = 11760 N·0.0125 m²/ 0.25 m²

Answer:

1) [tex]I=1.8*10^{-6}\: W/m^{2}[/tex]  

2) [tex]E=0.037 \: V/m[/tex]

Explanation:

1)

The intensity equation is given by:

[tex]I=\frac{P}{4\pi r^{2}}[/tex]

Where:

[tex]I=\frac{20000}{4\pi (30000)^{2}}[/tex]

[tex]I=1.8*10^{-6}\: W/m^{2}[/tex]  

2)

Now, the intensity and the electric field are related as:

[tex] I=0.5c\epsilon_{0}E^{2}[/tex]

Here:

We need to solve it for E.

[tex]E= \sqrt{\frac{2I}{c\epsilon_{0}}}[/tex]

[tex]E= \sqrt{\frac{2(1.8*10^{-6})}{(3*10^{8})(8.85*10^{-12})}}[/tex]

[tex]E=0.037 \: V/m[/tex]

I hope it helps you!

The final velocity of the boat is 4.22 m/s in opposite direction to the boater.

The final velocity of the boat is determined by applying the principle of conservation of linear momentum as follows;

Let the initial velocity of the boater and the boat = v

[tex]m_1 u_1 + m_2 u_2 = v(m_1 + m_2)\\\\76(2.5) + 45u_2 = 0(76 + 45)\\\\190 + 45u_2=0\\\\45u_2 = -190\\\\u_2 = \frac{-190}{45} \\\\u_2 = -4.22 \ m/s[/tex]

Thus, the final velocity of the boat is 4.22 m/s in opposite direction to the boater.

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Answer:

Explanation:

Let the separation required be d .

Force between rod = 10⁻⁷ x  2 I₁ I₂ L / d

where I₁ and I₂ are current in them , d is distance of separation and L is length of wire .

Force between rod = 10⁻⁷ x  2 x 1200 x  1200 x .69  / d

= .1987 /d

Restoring Force by spring = k x where k is force constant and x is compression .

= 130 x .03

= 3.9 N

For balancing

Restoring Force by spring = Force between rod

.1987 /d = 3.9

d = .1987 /3.9

= .0509 m

= 5.09 cm .

Answer:

Explanation:

vector A =(3i^+4J^-2k^),

let the required vector is B = x i^ + y j^

sqrt (x2 + y2) = 5,  

x2 + y2 = 25  ..............(1)

Since vector A and B are perpendicular to each other then,

A.B = 0

3x + 4 y = 0

y = -3x/4 ..............(2)

Solving these two equations we get x = 4 and y = -3;

hence vector B = 4 i^ -3 j^

Answer:

The force is being pulled my the gravity or it could be a third party thing like a black hole you feel me

Explanation:

Answer:

1)  T = 649.86 s, 2)   L₀ = L_f,   [tex]\frac{K_o}{K_f}[/tex] = 4.8

Explanation:

1) As the system of the two bodies is isolated, its angular momentum is conserved

initial instant.  r₀ = 155 m, T₀= 385.3 s

      L₀ = I₀ w₀

final instant. r = 119.35 m

      L_f = I w

      L₀ = L_f

      I₀ w₀ = I w

      w = [tex]\frac{I_o}{I} \ w_o[/tex]

let's consider each object as punctual

      I = m r²

at angle velocity and period are related

         w = 2pi / T

we substitute

      [tex]\frac{2\pi }{T} = \frac{m r^2}{m _o^2 } \ \frac{2\pi }{T_o}[/tex]

      [tex]\frac{1}{T} = ( \frac{r}{r_o} )^2 \ \frac{1}{T_o}[/tex]

       T = [tex](\frac{r_o}{r} )^2 \ T_o[/tex]

let's calculate

       T = [tex]( \frac{155}{119.35} )^2 \ 385.3[/tex]

        T = 649.86 s    

2) The angular momentum is conserved because the system is isolated.

Let's look for kinetic energy

        K_total = 2 K = 2 (½ I w²)

        K_total = I 4π² / T²

        K_total = 2m r² 4 π² / T²

for r = 155 m

         K₀ = 8π² m r₀² / T₀²

for r = 119.35 m

          K_f = 8π² m r² / T²

the relationship is

        [tex]\frac{K_o}{K_f} = ( \frac{r_o \ T}{ r \ \ T_o} )^2[/tex]

        [tex]\frac{K_o}{K} = ( \frac{ 155 \ \ \ 649.86}{ 119.35 \ 385.3})^2[/tex]

       [tex]\frac{K_o}{K_f}[/tex] = 4.8

Answer:

nuclear fission!!!

The nuclear fission is taken place in the given reaction.

          Nuclear fission reaction is the process how the larger energy particles hit by a neutron and separated into lighter elements with some energy. The lighter elements can exhibit energy in the form of electromagnetic radiation and in the form of kinetic energy.

        For an example, the most known nucleus is Uranium - 235. This Uranium - 235 has the half life period of 740 million years. The Uranium - 235 when bombarded with neutrons, this causes the U-235 nucleus to split, producing, on average, Barium-141, Krypton-91, and  three neutrons.

        The given reaction is thus a nuclear fission reaction.

Thus, Option A is the correct answer.

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Answer:

The pressure of the solid on the surface depends on the area of contact. The area of contact between the two surfaces. The greater the force or the smaller the area the greater the pressure.

(credits to the rightful owner for these answers :)

Answer:

All magnets have two poles: the North Pole and the South Pole.

Magnets attract ferromagnetic materials such as iron, nickel, and cobalt.

The magnetic force of a magnet is stronger at its poles than in the middle.

A freely suspended magnet always points in North-South direction.

Hope this helps

Answer:

(B) If frequency decreases wavelength increases

Answer

the medium does not change the speed of the on they should change.

Explanation:

The speed of the waves is constant for a given medium, depending on the physical properties of the medium,

When a wave is strapped on a wall of a medium it does not change the properties of the medium, the wave changes direction, but since the medium does not change the speed of the on they should change.

The proper time between two events is measured by clocks at rest in a reference frame in which the two events occur in Nashville occur at the same coordinates. So, option d.

The perspective from which you perceive and measure things is known as a reference frame. It's applied to describe how an object is moving or where it is.

Here,

Depending on the frame of reference, the time elapsed between two occurrences may vary, according to the Theory of Special Relativity.

The duration between two events occurring in the rest frame, as measured from a reference frame in motion relative to the rest frame, will always be longer than the correct time. Time dilation is a phenomenon that develops in accordance with the relativity of space and time.

A single clock that is present for both occurrences can be used to determine the right time difference between them.

The appropriate time between two events is the amount of time that elapses within a frame in which the two events take place at the same location, to put it another way.

Hence,

The proper time between two events is measured by clocks at rest in a reference frame in which the two events occur in Nashville occur at the same coordinates. So, option d.

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Answer:

a) [tex]V_2=8m/s[/tex]

b) [tex]P_2=9.54*10^4 Pa[/tex]

Explanation

From the question we are told that:

Initial Area of pipe  [tex]A_1=8.00 cm^2[/tex]

Initial Fluid flow speed [tex]r_1 =320 cm/s,\approx 320*10^{-2}[/tex]

Initial Pressure of [tex]\rho_1 =1.40*10^5 Pa[/tex]

Final area of pipe [tex]A_2 =3.70 *10^{-2} cm^2[/tex]

Density of acid [tex]\rho=1660kg/m^3[/tex]

a)

Generally the equation for continuity is mathematically given by

[tex]A_1V_1=A_2V_2\\\\V_2=\frac{A_1*V_1}{A_2}[/tex]

Since volume is directly proportional to rate of flow

[tex]V_2=\frac{8*320}{3.20} *10^{-2}[/tex]

[tex]V_2=8m/s[/tex]

b)

Generally the Bernoulli's equation is mathematically given by

[tex]p_1+\frac{1}{2}\rho v_1^2+\rho gh_1=P_2+\frac{1}{2}\rho v_2^2+\rho gh_2\\\\with\ h_1=h_2\\\\p_1+\frac{1}{2}\rho v_1^2=P_2+\frac{1}{2}\rho v_2^2[/tex]

Therefore

[tex]P_2=P_1+\frac{1}{2}\rho(v_1^2-V_2^2)\\\\P_2=(1.40*10^5)+\frac{1}{2}(1660)(v_1^2-V_2^2)[/tex]

[tex]P_2=9.54*10^4 Pa[/tex]

Solution :

Placing the[tex]$3 \ kg$[/tex] mass at the [tex]$\text{origin}$[/tex] and line up the square up with the axes.

[tex]$x_{cm} = \frac{\sum_i x_i m_i}{\sum_i m_i }$[/tex]

     [tex]$=\frac{1.5 a + 1.5a +0 +0}{7.5}$[/tex]

     [tex]$=\frac{3a}{7.5}$[/tex]

    [tex]$=\frac{2a}{5}$[/tex]

[tex]$y_{cm} = \frac{\sum_i y_i m_i}{\sum_i m_i }$[/tex]

     [tex]$=\frac{1.5 a + 1.5a +0 +0}{7.5}$[/tex]

     [tex]$=\frac{3a}{7.5}$[/tex]

    [tex]$=\frac{2a}{5}$[/tex]

Therefore,  r = [tex]$\sqrt2 \left(\frac{2a}{5}\right)$[/tex]

                           [tex]$=\frac{2 \sqrt2}{5}a$[/tex]

It s given that the side of the square is a = 32.2 cm

So, r [tex]$=\frac{2 \sqrt2}{5}a$[/tex]

       [tex]$=\frac{2 \sqrt2}{5}\times 32.2$[/tex]

       = 18.21 cm

So the distance of the 3 kg mass from the center of mass, r= 18.21 cm

An Particle a has Weston practical.

The resistance to motion of one object moving in relation to another is known as friction. It is not regarded as a fundamental force like gravity or electromagnetic, according to the International Journal of Parallel, Emergent and Distributed Systems(opens in new tab).

According to the book Soil Mechanics(opens in new tab), scientists started putting together the laws governing friction in the 1400s.

However, because the interactions are so complex, characterizing the force of friction in various circumstances typically requires experiments and can't be derived from equations or laws alone. There are numerous exceptions to every frictional general rule.

Therefore, An Particle a has Weston practical.

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Answer:

[tex]\lambda=1.03\times 10^{-3}\ m[/tex]

Explanation:

Given that,

The energy of the microwave oven is [tex]1.2\times 10^{-3}\ eV[/tex].

We need to find the wavelength of these photons.

[tex]1.2\times 10^{-3}\ eV=1.2\times 10^{-3}\times 1.6\times 10^{-19}\\\\=1.92\times 10^{-22}\ J[/tex]

The energy of a wave is given by :

[tex]E=\dfrac{hc}{\lambda}\\\\\lambda=\dfrac{hc}{E}[/tex]

Put all the values,

[tex]\lambda=\dfrac{6.63\times 10^{-34}\times 3\times 10^8}{1.92\times 10^{-22}}\\\\\lambda=1.03\times 10^{-3}\ m[/tex]

So, the wavelength of these photon is [tex]1.03\times 10^{-3}\ m[/tex].

Answer:

Speed of gamma rays = 3 x 10⁸ m/s

Explanation:

Given:

Frequency of gamma ray = 3 x 10¹⁹ Hz

Wavelength of gamma rays = 1 x 10⁻¹¹ meter

Find:

Speed of gamma rays

Computation:

Velocity = Frequency x wavelength

Speed of gamma rays = Frequency of gamma ray x Wavelength of gamma rays

Speed of gamma rays = [3 x 10¹⁹][1 x 10⁻¹¹]

Speed of gamma rays = 3 x [10¹⁹⁻¹¹]

Speed of gamma rays = 3 x [10⁸]

Speed of gamma rays = 3 x 10⁸ m/s

Answer:

Explanation:

The magnetic field is pointing upwards , so magnetic flux is upwards . Due to increase in area , magnetic flux in upward direction will increase . Hence according to Lenz's law , induced current will be such that it will try to counter this increase . It is possible if current is in clockwise direction . Due to it magnetic field will be induced in downward direction thus reducing the total magnetic flux.  

Hence direction of induced current will be clockwise direction in the loop as shown in the image enclosed .

Answer:

a ) 24 m/s

Explanation:

Given,

Frequency ( f ) = 6 Hz

Wavelength ( λ ) = 4 m

To find : Speed ( v ) = ?

Formula : -

v = f x λ

v

= 4 x 6

= 24 m/s

Therefore, the speed of a wave that has a frequency of 6 Hz and a wavelength of 4 m

is 24 m/s.

If two adjacent media have the same index of refraction, n, then the phenomenon is refraction.

Assuming two materials have the very same refractive index, the light goes through with next to no (or negligible) dissipating or refraction. The light voyages straight since it can't recognize any distinction between the two materials, thus the speed of traveling with as little luggage as possible doesn't change (twist).

Examples are eyes and prism.

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Explanation:

f=mg

=200×10

=200N

Now,

work done=df

25×200

=500J

Answer:

The frequency is  5.4 × 10^14Hz

Explanation:

The frequency of yellow-green light with a wavelength of 560 nm is approximately 5.4 x 10¹⁴ Hz.

The frequency of yellow-green light with a wavelength of 560 nm can be calculated using the formula:

frequency = speed of light/wavelength

Where the speed of light is approximately 3.0 x 10⁸ meters per second.

First, we need to convert the wavelength from nanometers to meters by dividing by 10⁹:

560 nm = 560 x 10⁻⁹ m

Then, we can plug in the values and calculate the frequency:

frequency = (3.0 x 10⁸ m/s) / (560 x 10⁻⁹ m)

frequency ≈ 5.4 x 10¹⁴ Hz

Therefore, yellow-green light with a wavelength of 560 nm has a frequency of approximately 5.4 x 1014 Hz.

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Explanation:

Given that,

The mass pulled down an additional 0.5 m and released.

The period of oscillation is 5 s

(a) The amplitude of the spring is equal to the maximum displacement i.e. 0.5 m.

(b) The full range of the vertical motion is (2×0.5) = 1 m.

(c) The frequency of the spring,

[tex]f=\dfrac{1}{T}\\\\=\dfrac{1}{5}\\\\=0.2\ Hz[/tex]

(d) The period of the spring is 5 seconds.

Always here to help. Bring it!!!

Answer: Johannes Kepler

Explanation:

Kepler discovered that Mars' orbit was an ellipsoid using the exact data that Tycho had obtained.

Answer:

u₂ = 3.7 m/s

Explanation:

Here, we use the law of conservation of momentum, as follows:

[tex]m_1u_1+m_2u_2=m_1v_1+m_2v_2\\[/tex]

where,

m₁ = mass of the car = 1250 kg

m₂ = mass of the truck = 2020 kg

u₁ = initial speed of the car before collision = 17.4 m/s

u₂ = initial speed of the tuck before collision = ?

v₁ = final speed of the car after collision = 6.7 m/s

v₂ = final speed of the truck after collision = 10.3 m/s

Therefore,

[tex](1250\ kg)(17.4\ m/s)+(2020\ kg)(u_2)=(1250\ kg)(6.7\ m/s)+(2020\ kg)(10.3\ m/s)\\\\(2020\ kg)(u_2) = 8375\ N.s + 20806\ N.s - 21750\ N.s\\\\u_2=\frac{7431\ N.s}{2020\ kg}[/tex]

u₂ = 3.7 m/s