A skateboarder rides down the street. When his feet push down on the
skateboard, what is the reaction force?

Answer:

The solenoid has 213 turns.

Explanation:

The number of the solenoid's turns (N) can be found as follows:

[tex] N = \frac{L*I}{\phi_{B}} [/tex]    (1)

Where:

L: is the self-inductance of the solenoid

I: is the current = 1.40 A

[tex]\phi_{B}[/tex]: is the magnetic flux = 0.00308 Wb      

The self-inductance of the solenoid (L) is:

[tex] L = \frac{|\epsilon|}{|dI/dt|} [/tex]   (2)

Where:

ε: is the induced emf = 12.2x10⁻³ V

dI/dt: is the rate changing of the current = 0.0260 A/s

By entering equation (2) into (1) we can find the number of turns:

[tex] N = \frac{|\epsilon|*I}{\phi_{B}|dI/dt|} = \frac{12.2 \cdot 10^{-3} V*1.40 A}{0.00308 Wb*0.0260 A/s} = 213 [/tex]        

Therefore, the solenoid has 213 turns.

I hope it helps you!

Answer:

Option d = all of the above.

Explanation:

This question is more of a driving lesson or tutorial Question and not that scientific, it is logical and the "rule" attached to reversing and driving that is operating of vehicles especially cars, trucks and so on.

All the options given in the Question from option 'a' to option 'c' are all correct when driving backwards that is reversing or backing . Driving backward(backing or reversing) is not as easy as during forward (drive mode).

=> " Position your right hand on the back of the passenger seat. Grip the steering wheel at the 12 o’clock position with your left hand"

REASON: FOR BALANCING.

=> " Move the wheel left or right in the direction in which you want the rear of the vehicle to go."

The above, given in the Question are all correct.

When backing straight or to the right, all of the mentioned options are correct and recommended practices are to Position your right hand on the back of the passenger seat. The correct option is option d.

a) Position your right hand on the back of the passenger seat: This is a technique used by some drivers to help them have a better sense of the vehicle's position and reference point while backing up.

b) Grip the steering wheel at the 12 o'clock position with your left hand: This hand position allows for better control and maneuverability of the steering wheel while backing up.

c) Move the wheel left or right in the direction in which you want the rear of the vehicle to go: This is the fundamental principle of steering while backing up. By turning the wheel in the desired direction, you can guide the rear of the vehicle in that direction.

Therefore, These practices can assist in improving control, visibility, and maneuverability while backing up, ensuring a safer and more effective backing maneuver. The correct option is option d.

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Answer:

52 g was lost as carbon dioxide to the atmosphere

Explanation:

When lead carbonate is heated, it decomposes into two components:

1. Lead oxide

2. carbon dioxide

While the lead oxide remains a yellow solid in the heating container, the carbon dioxide escapes into the atmosphere as a gas. The equation of the reaction is as below:

[tex]PbCO_3_{(s)} --> PbO_{(s)} + CO_2_{(g)}[/tex]

Hence, if a 150 g lead oxide is heated in a container and the final mass is 98 g, it means 52 g (150 - 98) of the total mass has been lost as carbon dioxide to the atmosphere.

Answer:

The gap between the plates will be 1.2 x 10^-15 m

No, this is not practically achievable.

Explanation:

Capacitance = 1.0 F

area of plate = 1.4 cm^2 = 1.4/10000 m^2 =  m^2

distance = ?

We use the equation

[tex]C[/tex] =  [tex]\frac{A}{d}[/tex]*ε

C is the capacitance

where A is the area

d is the distance of separation of plates

ε is the permeability of free space = 8.854×10^-12 F⋅m−1

substituting values, we have

1 = [tex]\frac{0.00014}{d}[/tex]* 8.854×10^-12

distance between plates = 1.2 x 10^-15 m

This is not practically achievable in real life

Answer:

Explanation:

Friction causes generation of heat and causes increased wear and tear.

The friction is a resistive force and is related to heat energy, so an increase in friction results in the generation of heat, so option D is correct.

Two solid objects cannot roll or slide over one another due to the force of friction. Although frictional forces can be useful, such as the traction needed to walk without slipping, they can also present a large degree of resistance to motion. Automobile engines need about 20% of their power to overcome frictional forces in moving parts.

The fundamental source of friction between metals appears to be the adhesion forces between the contact zones of the surfaces, which are always microscopically uneven. Friction is produced by shearing, these "welded" seams, and the rubbing action of the rougher, tougher surface against the softer, smoother surface.

The friction is a resistive force trying to oppose the force applied As friction is related to heat when we increase the heat, the friction increases, and vice versa.

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Answer:

This statement is not true

Explanation:

Because The normal magnetic field line points out from the north magnetic pole and in from the south magnetic pole.

Answer:

false

Explanation:

hope this helps :)

Answer:

D. AC+BD -> AD +BC

Explanation:

I got it right

A double displacement reaction is also called the double replacement reaction or double decomposition reaction. Here AC + BD → AD + BC is a double displacement reaction. The correct option is D.

A double displacement reaction is defined as a chemical reaction in which the positive and negative ions of two ionic compounds exchange their places to form two new compounds. The general form of a double displacement reaction is given as:

AC + BD → AD + BC

Here 'A' and 'B' are positively charged cations, whereas 'C' and 'D' are negatively charged anions. The double displacement reactions generally occur between the substances in an aqueous solution. In order for a reaction to occur, one of the products is usually a solid precipitate, a gas or a molecular compound like water.

Thus the correct option is D.

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Answer:

20 m

Explanation:

Given in the y direction:

Δy = 10 m

v₀ = 25 m/s sin 37° = 15.0 m/s

a = -10 m/s²

Find: t

Δy = v₀ t + ½ at²

10 m = (15.0 m/s) t + ½ (-10 m/s²) t²

10 = 15t − 5t²

2 = 3t − t²

t² − 3t + 2 = 0

(t − 1) (t − 2) = 0

t = 1 or 2

Since the projectile reaches Q before it reaches the peak, we want the lesser time, so t = 1.

Given in the x direction:

v₀ = 25 m/s cos 37° = 20.0 m/s

a = 0 m/s²

t = 1 s

Find: Δx

Δx = v₀ t + ½ at²

Δx = (20.0 m/s) (1 s) + ½ (0 m/s²) (1 s)²

Δx = 20 m

Answer:

Sa is the salary of the governor of state A

Sb  is the salary of the governor of state A

"The governor of state A earns $53,745 more than the governor of state B. "

This means that:

Sa = Sb + $53,745

"If the total of their salaries is $289,405,"

means that:

Sa + Sb = $289,405

Then we have two equations:

Sa = Sb + $53,745

Sa + Sb = $289,405

Now, we can replace the first equation into the second equation:

(Sb + $53,745) + Sb = $289,405

2*Sb = $289,405 - $53,745 = $235,660

Sb = ($235,660)/2 = $117,830

and:

Sa = Sb +  $53,745 =  $117,830 + $53,745 = $171,575

Governor of state A earns:  $171,575

Governor of state B earns:  $117,830

Answer:

Explanation:

the resistance of a electrical device

R = V² / P where V is volt and P is power .

The devices are in parallel so same volt will apply on them

So R₁ = 12² / 32.5 = 4.431 ohm

R₂ = 12² / 2 x 10³ = .072 ohm

when they are in series

Common Current in them = 12 / 4.431 + .072

= 2.6649 A

power consumed by first device when they are in series

= current² x resistance

= 2.6649² x 4.431 = 31.46 W

power consumed by other

= 2.6649² x .072  = .511 W

Answer:

the mass of one sun

Explanation:

its really heavy

Answer:

Explanation:

We shall apply gas law formula to get the solution .

P₁ V₁ / T₁ = P₂ V₂ / T₂

P₁ = 10⁵ + 18 x 10³ x 9.8  where 10⁵ Pa is atmospheric  pressure at surface

= 1.764 x 10⁵ + 10⁵

= 2.764 x 10⁵

2.764 x 10⁵  x 3 / ( 273 + 9 ) = 10⁵ x V₂ / ( 273 + 22 )

V₂ = 8.67 cm³

Answer:

See below

Explanation:

We know that the unit of pressure is Pascal.

We have,

Pressure = [tex] \frac{force}{area} [/tex]

[tex] = \frac{m \times g}{l \times b} [/tex]

[tex] = \frac{kg \: \times \: {meter \: per \: second \: }^{2} }{ {m}^{2} } [/tex]

[tex] = kg \: {m}^{ - 1} \: {s}^{ - 2} [/tex]

The unit of pressure i.e Pascal is derived unit because it is expressed depending on more than two units i.e kg / [ m × s × s ]

Hope this helps..

best regards!!

Answer:

1.) 440 Hz

2.) 659.3 Hz

Explanation:

1.) Given parameters are:

wavelength = 0.77955 m.

speed of sound = 343.00 m/s

Frequency = speed/ wavelength

Substitute speed and wavelength into the formula

Frequency = 343/ 0.77955

Frequency = 439.99

Frequency = 440 Hz approximately

2.) The parameters given are:

wavelength = 0.52028 m.

speed of sound = 343.00 m/s

Using the same formula

Frequency = speed/wavelength

Substitute all the parameters into the formula

Frequency = 343 / 0.52028

Frequency = 659.3 Hz approximately

The pitch of a note depends on the frequency of the sound waves.

The pitch of a sound increases as the frequency of the sound waves increases.

Answer:

1.) 440 Hz

2.) 659.3 Hz

Explanation:

1.) Given parameters are:

wavelength = 0.77955 m.

speed of sound = 343.00 m/s

Frequency = speed/ wavelength

Substitute speed and wavelength into the formula

Frequency = 343/ 0.77955

Frequency = 439.99

Frequency = 440 Hz approximately

2.) The parameters given are:

wavelength = 0.52028 m.

speed of sound = 343.00 m/s

Using the same formula

Frequency = speed/wavelength

Substitute all the parameters into the formula

Frequency = 343 / 0.52028

Frequency = 659.3 Hz approximately

The pitch of a note depends on the frequency of the sound waves.

The pitch of a sound increases as the frequency of the sound waves increases.

Answer:

The magnitude and direction of the force per unit length of one wire on the other is 2 x 10⁻⁵ N/m, attractive force.

Explanation:

Given;

distance between the two parallel wires, r = 10 cm = 0.1 m

current in the first wire, I₁ = 2A

current in the second wire, I₂ = 5 A

The force per unit length on each wire can be calculated as;

[tex]\frac{F}{L} = \frac{\mu_oI_1I_2}{2\pi r}[/tex]

where;

μ₀ is permeability of free space = 4π x 10⁻⁷ m/A

[tex]\frac{F}{L} = \frac{\mu_oI_1I_2}{2\pi r} \\\\\frac{F}{L} = \frac{4\pi*10^{-7}*2*5}{2\pi *0.1} \\\\\frac{F}{L} = 2 *10^{-5} \ N[/tex]/ m

The direction of the force between the two wires is attractive since the current in the two wires are in opposite direction.

Therefore, the magnitude and direction of the force per unit length of one wire on the other is 2 x 10⁻⁵ N/m, attractive force.

If we launched a very fast dart from the Space Shuttle in a direction away from any planet, Assuming the dart is traveling at an extremely high speed (close to the speed of light), it might eventually encounter a cloud of interstellar gas or dust.

Space is mostly empty, consisting of a vacuum with very low density. However, space also contains various astronomical objects, such as stars, planets, moons, asteroids, comets, and other celestial bodies.

There is also interstellar gas and dust scattered throughout space, which can sometimes form clouds that give birth to new stars. Additionally, space is permeated by electromagnetic radiation, including cosmic rays, X-rays, ultraviolet radiation, visible light, infrared radiation, and radio waves.

Space also contains various forms of energy, including dark energy, which is believed to be responsible for the accelerating expansion of the universe, and dark matter, which is thought to make up the majority of the matter in the universe but cannot be directly observed. Overall, space is a vast and complex environment that continues to fascinate astronomers and scientists.

Here in this question,

Therefore, if launched a very fast dart from the Space Shuttle, is pointed in some direction away from any planet, it could travel beyond the solar system. it would be most likely to hit a cloud of interstellar gas or dust. first after traveling outward for a while.

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a).  frequency = (speed) / (wavelength)

The speed of light is around 3 x 10⁸ m/s.

For 380 nm (violet light), frequency = (3 x 10⁸ m/s) / (380 x 10⁻⁹ m)

Frequency = 7.89 x 10¹⁴ Hz

For 760 nm (red light), frequency = (3 x 10⁸ m/s) / (760 x 10⁻⁹/s)

Frequency = 3.94 x 10¹⁴ Hz

The ratio is 2 .

That's 1 octave, or 0.3 of a decade.

b).  The ratio of highest/lowest sounds is (20,000 Hz/20 Hz) = 1,000

That's 3 decades, or about 10 octaves.

===> Speaking logarithmically ( ! ), ears are sensitive to a range of sound frequencies that's 10 times as wide as the range of light frequencies that eyes can detect.

Answer:

59%

Explanation:

Data obtained from the question include the following:

Input temperature = 495 K

Output temperature = 293 K

Efficiency =?

The efficiency of the car engine can be obtained by multiplying the ratio of the output temperature to the input temperature by 100 as shown below:

Efficiency = output /input x 100

Efficiency = 293/495 x 100

Efficiency = 59.1 ≈ 59%

Therefore, the efficiency of the car engine is approximately 59%

Answer:

2.5 kg/m³

Explanation:

Absolute pressure = gauge pressure + atmospheric pressure

P = Pg + Pa

The gauge pressure caused by the weight of a fluid is called the static pressure.  It is equal to the density of the fluid × acceleration due to gravity × depth of the fluid,

Pg = ρgh

Therefore:

P = ρgh + Pa

300 Pa = ρ (10 m/s²) (8.00 m) + 100 Pa

ρ = 2.5 kg/m³

Answer:

a)   L = 440 cm

Explanation:

In the open tube on one side and cowbell on the other, we have a maximum in the open part and a node in the closed part, therefore the resonance frequencies are

             λ₁ = 4L             fundamental

             λ₃ = 4L / 3       third harmonic

             λ₅ = 4L / 5       five harmonic

The violin string is a fixed cure in its two extracts, so both are nodes, their length from resonance wave are

              λ₁ = 2L                    fundamental

             λ₂ = 2L / 2              second harmonic

             λ₃ = 2L / 3              third harmonic

             λ₄= 2L / 4               fourth harmonic

They indicate that resonance occurs in the fourth harmonic, let's look for the frequency

              v =λ f

for the fundamental

              v = λ₀ f₀

              V = 2L f₀

for the fourth harmonica

              v = λ₄  f ’

              v = L / 2  f'

             2L f₀ = L / 2 f ’

             f ’= 4 f₀

             f ’= 4 440

             f ’= 1760 Hz

for this frequency it has the resonance with the tube

           f ’= 4L

           L = f ’/ 4

           L = 1760/4

           L = 440 cm

b) let's find the frequency of the next harmonic in the tube

             λ₃ = 4L / 3

             λ₃ = 4 400/3

             λ₃ = 586.6 cm

            v = λf

            f = v / λlam₃

            f₃3 = 340 / 586.6

            f3 = 0.579

as the minimum frequency on the violin is 440 Beam there is no way to reach this value, therefore there are no higher resonances

Answer:

B. they have less mass than their reactants

Explanation:

In both nuclear fission and nuclear fusion, the products have less mass than their reactants. So, option B is correct.

Nuclear reaction is defined as the reaction that involves the collision between one or more atomic nuclei and a highly energetic subatomic particle to produce one or more nuclei along with the emission of a large amount of energy.

Here,

Nuclear fission and fusion are two types of nuclear reactions that involves the production of large amount of energy from atomic nuclei.

Nuclear fission is the nuclear reaction in which a heavier nucleus is split into two or more lighter nuclei, under radioactive condition, with the release of a massive amount of energy.

Nuclear fusion is the nuclear reaction in which two or more lighter nuclei nuclei fuse together under radioactive condition and forms a heavier nuclei and by releasing a large amount of energy.

In both nuclear fission and nuclear fusion, there occurs a release of large amount of energy. This is because most of the mass of the reactants is converted into energy which is known as the mass-energy. So the products of these nuclear reactions will have lesser mass than their reactants.

Hence,

In both nuclear fission and nuclear fusion, the products have less mass than their reactants.

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Explanation:

Power = work / time

Power = force × distance / time

P = (650 kg) (10 m/s²) (20 m) / (15 s)

P = 8667 W

Answer:

yeah this statement is tru

Explanation:

it is because the speed of the bullet is more than the speed of rolling ball .so from this reason we cannot catch a bullet.

A bullet will be moving much faster than a rolling ball. Even seeing a bullet in flight requires it to be extremely low velocity.

Answer:

Is radiation of sufficient energy to produce ions.

Is radiation of sufficient energy to remove electrons from atoms.

Explanation:

Ionization radiation is a radiation that travels at a high speed, and possesses sufficient speed to knock electrons off of an atom or a molecule, ionizing the atom. Ionization radiation can be made of travelling subatomic particles, or an electromagnetic wave with high energy, usually the types found at the end of the electromagnetic spectrum. Some subatomic particles that produce ionization are alpha particle, beta particles, and neutron. The electromagnetic waves with ionization abilities includes Gamma rays. -rays, and high energy ultraviolet rays.

Answer:

165.529454

Explanation:

According to the Pythagorean Theorem for calculating the lengths of a right angle triangle's sides, a^2 + b+2 = c^2, where c is the longest side (and the side opposing the right angle). So in your case it would be 150*150 + 70*70 = 27400. And √ 27400 is your answer.

Answer:

The relative velocity of an object A with respect to another object B.

Explanation:

The relative velocity of an object A with respect to another object B is the velocity that object A would appear to have to an observer situated on object B moving along with it.

Answer:

The answer is B.

Explanation:

Given that the current (Ampere) in a series circuit is same so we can ignore it. We can assume that the total voltage is 60V and all the 3 resistance are different, 20Ω, 40Ω and 60Ω. So first, we have to find the total resistance by adding :

Total resistance = 20Ω + 40Ω + 60Ω

= 120Ω

Next, we have to find out that 1Ω is equal to how many voltage by dividing :

120Ω = 60V

1Ω = 60V ÷ 120

1Ω = 0.5V

Lastly, we have to calculate the voltage at R1 so we have to multiply by 20 (R1) :

1Ω = 0.5V

20Ω = 0.5V × 20

20Ω = 10V

if it is horizontal line, that means position is same but time is increasing.

velocity=0 . particle is not even moving

Answer:

The deviation of a mirror is equal to twice the angle of incidence.The total angle between the straight-line path and the reflected ray is twice the angle of incidence. This is called the deviation of the light and measures the angle at which the light has strayed from its initial straight-line path.

HOPE IT HELPS :)

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Answer:

A. 5.08 secs.

B. 10.16 secs.

C. 126.50 m.

D. 373.36 m

Explanation:

Data obtained from the question include the following:

Initial velocity (u) = 65 m/s

Angle of projection θ = 50°

A. Determination of the time taken to reach the peak.

Initial velocity (u) = 65 m/s

Angle of projection θ = 50°

Acceleration due to gravity (g) = 9.8 m/s²

Time (t) =.?

t = u•Sine θ/g

t = (65 × Sine 50) /9.8

t = 5.08 secs.

B. Determination of the total time spent by the ball in air.

Time (t) taken to reach the peak = 5.08 secs.

Total time (T) spent by the ball in air =?

T = 2t

T = 2 × 5.08

T = 10.16 secs

Therefore, the total time spent by the ball in air is 10.16 secs.

C. Determination of the maximum height.

Initial velocity (u) = 65 m/s

Angle of projection θ = 50°

Acceleration due to gravity (g) = 9.8 m/s²

Maximum height (H) =..?

H = u²•Sine² θ / 2g

H = 65² × (Sine 50)² / 2 × 9.8

H = 4225 × (Sine 50)² /19.6

H = 126.50 m

Therefore, the maximum height reached by the ball is 126.50 m.

D. Determination of the horizontal distance travelled by the ball.

Initial velocity (u) = 65 m/s

Angle of projection θ = 50°

Acceleration due to gravity (g) = 9.8 m/s²

Horizontal distance (R) =..?

R = u²•Sine 2θ / g

R = 65² × Sine (2×30) / 9.8

R = (4225 × Sine 60) / 9.8

R = 373.36 m

Therefore, the horizontal distance travelled by the ball is 373.36 m