A student is comparing the speed of sound in air and water. She measures the frequency, f, and wavelength, λ, of sound waves in both air and water. The results are shown in the following table. Based on her data, how does the speed of sound in water compare to the speed of sound in air?

A.The speed of sound through water is 4.3 times faster than sound through air.
B.The speed of sound through water is 2.6 times slower than sound through air.
C.The speed of sound through water is 8.4 times faster than sound through air.
D.The speed of sound through air is approximately equal to the speed of sound through water.

Answer:

ocean covers 71 percent of the earth

Answer:

the ocean  covers 71 percent of Earth's surface.

Explanation:

Answer:

[tex]F=32.24N[/tex]

Explanation:

From the question we are told that:

Height [tex]h= 2.75 m[/tex]

Length[tex]l = 5.25 m[/tex]

Mass [tex]m=45kg[/tex]

Final speed [tex]v_f=6.81[/tex]

Generally the equation for Potential Energy P.E is mathematically given by

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

Therefore

Initial potential energy

[tex]P.E_1=45*9.8*2.75 \\\\P.E_1= 1212.75 J[/tex]

Generally the equation for Kinetic Energy K.E is mathematically given by

[tex]K.E=0.5mv^2[/tex]

Therefore

Final kinetic energy

[tex]K.E_2= 1/2*45*6.81*6.81 \\\\K.E_2= 1043.46J[/tex]

Generally the equation for Work_done is mathematically given by

[tex]W=P.E_1-K.E_2\\\\W=169.3[/tex]

Therefore

[tex]F=\frac{W}{d}\\\\F=\frac{169.3}{5.25}[/tex]

[tex]F=32.24N[/tex]

Answer:

Explanation:

The vehicle is experiencing a large force created by the concrete wall.

Equation

vf^2 = vi^2 + 2*a * d

Givens

vf = 0   The car eventually does stop.

vi = 72 km/hr * [ 1000 m/  km] * [1 hour / 3600 seconds]

vi = 20 meters / second

a = ?

m = 850 kg

Solution

vf^2 = vi^2 + 2a*d

0 = 20 m/s + 2* 2 *a

-20 m/s = 4a

-20/4 =   a

a = - 5 m/s^2   The minus sign tells you the vehicle is slowing down. It sure should be.

Force = m * a

F = - 850 * (-5)

F =  - 4250 N

The car provides a 4250 N force on it going east to west and a 4250 N force going from west to east provided by the concrete wall.

Answer:

The weight of the planet is 29083.5 N .

Explanation:

mass of satellite, m = 6463 kg

height of orbit, h = 4.82 x 10^5 m

period, T = 2 h

radius of planet, R = 4.29 x 10^6 m

Let the acceleration due to gravity at the planet is g.

[tex]T = 2\pi\sqrt\frac{(R+h)^3}{gR^2}\\\\2\times 3600 = 2\times3.14\sqrt\frac{(4.29+0.482)^3\times10^{18}}{g\times 4.29\times 4.29\times 10^{12} }\\\\24.2 g =108.67\\\\g = 4.5 m/s^2[/tex]

The weight of the satellite at the surface of the planet is

W = m g = 6463 x 4.5 = 29083.5 N

Answer:

Explanation:

1 minute =60 second

power=work done/time taken

=2500/60

=41.66 watt

work=force *displacement

=500 N * 100 m

=50000 joule

Answer:

Explanation:

The force acting on an object given it's mass and acceleration can be found by using the formula

force = mass × acceleration

From the question we have

force = 1.5 × 10⁴ × 1.5

We have the final answer as

Hope this helps you

Answer:

[tex]\mu = 3.36\times 10^{-3}\ A-m^2[/tex]

Explanation:

Given that,

The magnitude of magnetic field, B = 0.55 T

The radus of the loop, r = 43 cm = 0.43 m

The current in the loop, I = 5.8 mA = 0.0058 A

We need to find the magnetic moment of the loop. It is given by the relation as follows :

[tex]\mu = AI\\\\\mu=\pi r^2\times I[/tex]

Put all the values,

[tex]\mu=\pi \times (0.43)^2\times 0.0058\\\\=3.36\times 10^{-3}\ A-m^2[/tex]

So, the magnetic moment of the loop is equal to[tex]3.36\times 10^{-3}\ A-m^2[/tex].

Answer:

a)    λ = 0.5346 10⁻⁹ m,  b)  1.13

Explanation:

a) The wave-particle duality is

       λ = [tex]\frac{\hbar }{p}[/tex]

the expression for energy kinetic is

      E = p² / 2m

energy is also related to temperature

      E = [tex]\frac{3}{2} \ kT[/tex]

we substitute

      p =

     λ =

Rubidium's mass is m = 85 uma

we calculate

     λ =

     λ=

     λ = 0.5346 10⁻⁹ m

b) the relationship of the two lengths is

           λ /0.47 nm = 0.53 / 0.47 = 1.13

Answer:

Energy Flow

The chemical energy of food is the main source of energy required by all living organisms. This energy is transmitted to different trophic levels along the food chain. This energy flow is based on two different laws of thermodynamics:

First law of thermodynamics, that states that energy can neither be created nor destroyed, it can only change from one form to another.

Second law of thermodynamics, that states that as energy is transferred more and more of it is wasted.

Energy Flow in Ecosystem

The energy flow in the ecosystem is one of the major factors that support the survival of such a great number of organisms. For almost all organisms on earth, the primary source of energy is solar energy. It is amusing to find that we receive less than 50 per cent of the sun’s effective radiation on earth. When we say effective radiation, we mean the radiation, which can be used by plants to carry out photosynthesis.

Explanation:

Energy Flow in Ecosystem

The energy flow in the ecosystem is one of the major factors that support the survival of such a great number of organisms. For almost all organisms on earth, the primary source of energy is solar energy. It is amusing to find that we receive less than 50 per cent of the sun’s effective radiation on earth. When we say effective radiation, we mean the radiation, which can be used by plants to carry out photosynthesis.  

Most of the sun’s radiation that falls on the earth is usually reflected back into space by the earth’s atmosphere. This effective radiation is termed as the Photosynthetically Active Radiation (PAR).

Overall, we receive about 40 to 50 percent of the energy having Photosynthetically Active Radiation and only around 2-10 percent of it is used by plants for the process of photosynthesis. Thus, this percent of PAR supports the entire world as plants are the producers in the ecosystem and all the other organisms are either directly or indirectly dependent on them for their survival.

The energy flow takes place via the food chain and food web. During the process of energy flow in the ecosystem, plants being the producers absorb sunlight with the help of the chloroplasts and a part of it is transformed into chemical energy in the process of photosynthesis.

This energy is stored in various organic products in the plants and passed on to the primary consumers in the food chain when the herbivores consume (primary consumers) the plants as food. Then conversion of chemical energy stored in plant products into kinetic energy occurs, degradation of energy will occur through its conversion into heat.

Then followed by the secondary consumers. When these herbivores are ingested by carnivores of the first order (secondary consumers) further degradation will occur. Finally, when tertiary consumers consume the carnivores, energy will again be degraded. Thus, the energy flow is unidirectional in nature.

Moreover, in a food chain, the energy flow follows the 10 percent law. According to this law, only 10 percent of energy is transferred from one trophic level to the other; rest is lost into the atmosphere. This is clearly explained in the following figure and is represented as an energy pyramid.

Answer:

i think it could be d

Explanation:

I'm not sure

The sum of the vectors plotted below describes by 2x i + 4y j. Hence, option (B) is correct.

Physical quantities that exhibit both magnitude and direction are referred to as vector quantities. As an illustration, consider displacement, force, torque, momentum, acceleration, and velocity.

It is more complicated to add vectors than it is to add scalars. It is impossible to simply add two vectors together to get their sum since vectors include both magnitude and direction. The Triangle law is used to calculate the vector addition.

According to the figure:

the sum of the vectors is position vector of second vector, that is,  r = 2x i + 4y j.

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Answer

One molecule of water

Answer:

[tex]m=1.47\times 10^{-24}\ Kg[/tex]

Explanation:

Given that,

Charge, [tex]q=1.6\times 10^{-19}\ C[/tex]

Revolution = 7 rev

magnetic field, B = 45 mT

Time, t = 1.29 ms

We need to find the mass of the ion. Let m be the mass. The formula for the mass in terms of time period is given by :

[tex]m=\dfrac{qBT}{2\pi}\\\\m=\dfrac{1.6\times 10^{-19}\times 45\times 10^{-3}\times 1.29\times 10^{-3}}{2\pi}\\\\m=1.47\times 10^{-24}\ Kg[/tex]

So, the mass of the ion is equal to [tex]1.47\times 10^{-24}\ Kg[/tex].

Answer:

When converting chemical potential energy to kinetic energy some of the energy is lost as heat.

Explanation:

Given that,

Three resistors 4ohms 6ohms 8ohms are connected in series and are connected to cell of EMF 60volt.

The equivalent resistance in series combination is given by :

R = R₁ + R₂ +R₃

Put all the values,

R = 4 + 6 + 8

R = 18 ohms

Let I is the current in circuit. So,

[tex]I=\dfrac{V}{R}\\\\I=\dfrac{60}{18}\\\\I=3.33\ A[/tex]

Potential difference in 4 ohms,

[tex]V_1=IR_1\\\\V_1=3.33\times 4\\\\=13.32\ V[/tex]

Potential difference in 6 ohms,

[tex]V_2=IR_2\\\\V_2=3.33\times 6\\\\=19.98\ V[/tex]

Potential difference in 8 ohms,

[tex]V_3=IR_3\\\\V_3=3.33\times 8\\\\=26.64\ V[/tex]

Terminal potential difference in circuit is :

V = IR

Put all the values,

V = 3.33 × 18

V = 59.94 volts

Hence, this is the required solution.

Use the work-energy theorem. The total work done on the plane is equal to the change in its kinetic energy:

W = ∆K

W =  1/2 (1.5 kg) (6 m/s)² - 1/2 (1.6 kg) (8 m/s)²

W = -21 J

(Note that the work must be negative since the "braking" force opposes the direction in which the plane is moving.)

Answer:

Tension = 1.38 N

Explanation:

Given that:

Mass of block A [tex]m_A[/tex] = 2.9 kg

mass of block B [tex]m_B[/tex] = 0.87 kg

Force F = 6 N

Assume a = acceleration of the blocks.

Then:

[tex]m_A[/tex] (a) + [tex]m_B[/tex] (a) = 6

2.9a + 0.87a = 6

3.77a = 6

a = 6/3.77

a = 1.59 m/s²

Suppose T to be the tension in the string.

If we take a look at the forces acting on the first block, then:

F - T = [tex]m_A[/tex] (a)

T = F - [tex]m_A[/tex] (a)

T = 6 - 2.9(1.59)

T = 6 - 4.62

T = 1.38 N

Answer:

Explanation:

Note the connection between D-L-H shorts out the resistors on the right. Those 4 resistors can be ignored.

The connection between D-L-K means the 2 resistors between C-D and C-K are in parallel. The equivalent resistance of 2 6-ohm resistors in parallel is 3 ohms.

Similarly the connection between K-L-H means the 2 resistors between J-K and J-H are in parallel. The equivalent resistance of 2 6-ohm resistors in parallel is 3 ohms.

Adding the resistors in series together:

A-C-L-J-D = 6 + 3 + 3 + 6

= 18 ohms

Answer:

The torque is 0.31 Nm.

Explanation:

Electrical energy, E = 8400 J

time, t = 1 min

Angular speed, w = 2900 rpm = 303.53 rad/s

efficiency = 2/3 of input power

The toque is given by  

[tex]P =\tau w\\\\\frac{2}{3}\times \frac{E}{t}=\tau w\\\\\frac{2}{3}\times \frac{8400}{60}=\tau \times 303.53\\\\\tau =0.31 Nm[/tex]

Answer:

1.40 m/s

Explanation:

The potential energy of a compressed spring can be expressed as:

[tex]E_{ps}=\dfrac{1}{2}kx^2[/tex]

From above;

k = spring constant

x = distance of the spring (compressed)

From the barrel, the kinetic energy (i.e. the final K.E) of the ball is calculated using the relation:

[tex]E_{kf}= \dfrac{1}{2}mv^2[/tex]

where;

m = the ball mass

v = ball's speed

Equating both equations above, we have:

[tex]E_{ps}- F_fd=E_{kf[/tex]

This can be re-written as:

[tex]\dfrac{1}{2}kx^2 - F_fd=\dfrac{1}{2}mv^2}[/tex]

[tex]v^2 = (\dfrac{k}{m})x^2-\dfrac{2F_fd}{m}[/tex]

[tex]v =\sqrt{ (\dfrac{k}{m})x^2-\dfrac{2F_fd}{m}}[/tex]

replacing the values from the given information:

[tex]v =\sqrt{ (\dfrac{8.00\ N/m}{5.30\times10^{-3} \ kg})(5.00 \ cm \times \dfrac{10^{-2} \ m}{1 \ cm})^2-(\dfrac{2(0.032 \ N)(0.150 \ m)}{5.30\times \dfrac{10^{-3} \ kg}{1 \ g}})}[/tex]

[tex]v = \sqrt{1.962264151}[/tex]

v ≅ 1.40 m/s

The speed at which the projectile leaves the barrel of the cannon will be given as [tex]v=1.40\ \frac{m}{s}[/tex]

Speed is defined as the movement of any object with respect to time. It is the ratio of distance and time.

Now it is given in the question:

Mass of ball m = 5.30 g

The deflection of spring = 5 cm

The force constant of spring  [tex]k= 8 \ \frac{N}{m^2}[/tex]

The length of the barrel = is 15 cm

The frictional force of the barrel = 0.032 N

Now from the conservation of energy, we can write as

[tex]E_{spring}-E_{friction}=E_{ball}[/tex]

[tex]\dfrac{1}{2} kx^2-F_fd=\dfrac{1}{2} mv^2[/tex]

[tex]v=\sqrt{\dfrac{k}{m}(x^2) -\dfrac{2F_fd}{m} }[/tex]

Now putting the values in the above formula:

[tex]v=\sqrt{\dfrac{8}{5.30\times 10^{-3}}(15\times10^{-2}) -\dfrac{2\times(0.0032)\times (0.015)}{5.30\times 10^{-3}} }[/tex]

[tex]v=1.40\ \frac{m}{s}[/tex]

Thus the speed at which the projectile leaves the barrel of the cannon will be given as [tex]v=1.40\ \frac{m}{s}[/tex]

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Answer:

B

Explanation:

Cause its true

Answer:

the magnitude and direction of the uniform electric field is 1846.38 N/C and UPWARD respectively

Explanation:

Given the data in the question;

mass m = 1.30 g = 1.30 × 10⁻³ kg

Charge q = +6.90 µC = 6.90 × 10⁻⁶ C

we know that; g = 9.8 m/s

assuming gravity and the electrostatic force are the only forces exerted on the particle, hence the relation is;

F = mg and F = Eq

so

mg = Eq

make E subject of formula

E = mg / q

so we substitute

E = [ (1.30 × 10⁻³) × 9.8 ]  / 6.90 × 10⁻⁶

E = 0.01274 / 6.90 × 10⁻⁶

E = 1846.38 N/C

Since the charge is positive ( + ), { direction is Upward }

Therefore, the magnitude and direction of the uniform electric field is 1846.38 N/C and UPWARD respectively

Answer:

V = 8.34m/s

Explanation:

Given that

1/2ke^2 = 1/2mv^2 ......1

Where e = 3.75cm = (3.75/100)m

e = 0.0375m

K = 500 N/m

m = 10g = 10/1000

= 0.01kg

Substitute the values into equation 1

0.5×500×(0.0375)^2 = 0.5×0.01×v^2

250×0.001395 = 0.005v^2

0.348 = 0.005v^2

v^2 = 0.348/0.005

v^2 = 69.6

V = √69.6

V = 8.34m/s

The ball launches at the speed of V = 8.34m/s

Answer:

4 secs

Explanation:

The first step is to calculate the velocity

V= frequency × wavelength

= 500× 0.2

= 100

Therefore the time can be calculated as follows

= distance/velocity

= 400/100

= 4 secs

Answer:

F' = F

Explanation:

The gravitational force of attraction between two objects can be given by Newton's Gravitational Law as follows:

[tex]F = \frac{Gm_1m_2}{r^2}[/tex]

where,

F = Force of attraction

G = Universal gravitational costant

m₁ = mass of first object

m₂ = mass of second object

r = distance between objects

Now, if the masses and the distance between them is doubled:

[tex]F' = \frac{G(2m_1)(2m_2)}{(2r)^2}\\\\F' = \frac{Gm_1m_2}{r^2}[/tex]

F' = F

Answer:

42.1%

Explanation:

Applying,

E(%) = (M.A/V.R)×100............. Equation 1

Where E(%) = Percentage efficiency, M.A = mechanical advantage, V.R = Velocity ratio.

But,

M.A = L/E............... Equation 2

Where L = Load, E = Effort.

From the question,

Given: L = 150 N, E = 200 N

Substitute these values into equation 2

M.A = 200/150

M.A = 1.33

Also,

V.R for Inclined plane = 1/sin∅ =

V.R = 1/sin∅............... Equation 2

Where ∅ = angle of the inclined plane.

Where,

tan∅ = 4/12

∅ = tan⁻¹(4/12)

∅ = 18.43°

Therefore,

V.R = 1/sin18.43

V.R = 3.16.

Substituting the value of M.A and V.R into equation 1

E(%) = (1.33/3.16)×100

E(%) = 42.1%