3)
an electrical heater raises the temperature of a measured
quantity of water. six thousand joules of energy is absorbed
by the water from the heater in 30.0 seconds. what is the
minimum power rating of the heater?
a) 2.00 x10 w
c) 5.00 x10 w
b) 2.00 x10- w
d) 1.80 x 105w

The efficiency of a single movable pulley is not 100 % because the applied load is half of the load to be lifted.

MA = Fo / Fi

MA = Mechanical advantage

Fo = Output force

Fi = Input force

In a single movable pulley,

Fi = 0.5 Fo

MA = Fo / 0.5 Fo

MA = 2

Efficiency = MA * 100

Efficiency = 2 * 100

Efficiency = 200 %

A movable pulley does no have a fixed axis of rotation. In a movable pulley the forces are multiplied at the other end. So the effort required to pull the load is easier than a fixed pulley.

Therefore, the efficiency of a single movable pulley is not 100%

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Answer:

can you make it clear i do not understand.

Explanation:

Object distance, u = 26.0 cm

Focal length, f = -14.0 cm

Image distance, v = ?

The relationship between object distance, image distance, and focal length is:

Magnigication is calculated as:

The magnification of the object = 0.35

Answer:

6.002

6.020

6.023

6.302

Explanation:

The voltage drop across the 18 kΩ resistor is 90 volts. This means that when a current of 5 mA flows through an 18 kΩ resistor, there is a potential difference of 90 volts across the resistor.

To calculate the voltage drop across a resistor, Ohm's Law can be applied. Ohm's Law states that the voltage (V) across a resistor is equal to the product of the current (I) flowing through it and the resistance (R) of the resistor. The formula for Ohm's Law is V = I * R.

Given:

Current (I) = 5 mA = 5 * 10^(-3) A

Resistance (R) = 18 kΩ = 18 * 10^(3) Ω

Using Ohm's Law, we can calculate the voltage drop (V):

V = I * R

= (5 * 10^(-3) A) * (18 * 10^(3) Ω)

= 90 V

Therefore, the voltage drop across the 18 kΩ resistor is 90 volts. This means that when a current of 5 mA flows through an 18 kΩ resistor, there is a potential difference of 90 volts across the resistor.

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Answer:

v = 20.31 m/s

Explanation:

p = mv -> v = p/m = 32,500 kg*m/s / 1,600 kg = 20.31 m/s

To find the induced emf in the coil, we can use Faraday's law of electromagnetic induction, which states that the emf induced in a coil is equal to the rate of change of magnetic flux through the coil.

The magnetic flux through the coil can be calculated using the formula:

Φ = B * A * cosθ,

where B is the magnetic field, A is the area of the coil, and θ is the angle between the magnetic field and the normal to the coil.

Given:

B_initial = 0.50 T (initial magnetic field)

B_final = 2.5 T (final magnetic field)

θ = 60° (angle between the magnetic field and vertical)

r = 2.0 cm = 0.02 m (radius of the coil)

N = 100 (number of turns)

Δt = 0.40 s (change in time)

First, let's calculate the change in magnetic flux (ΔΦ):

ΔΦ = B_final * A * cosθ - B_initial * A * cosθ,

The area of the coil (A) can be calculated as the area of a circle:

A = π * r^2,

Now, substitute the values and calculate ΔΦ:

ΔΦ = (2.5 T) * (π * (0.02 m)^2) * cos(60°) - (0.50 T) * (π * (0.02 m)^2) * cos(60°).

Next, we can calculate the average rate of change of magnetic flux (ΔΦ/Δt):

average rate = ΔΦ / Δt.

Finally, we can find the induced emf (ε) by multiplying the average rate of change of magnetic flux by the number of turns in the coil:

ε = N * (ΔΦ/Δt).

Now, substitute the values and calculate the induced emf:

ε = 100 * ((2.5 T) * (π * (0.02 m)^2) * cos(60°) - (0.50 T) * (π * (0.02 m)^2) * cos(60°)) / (0.40 s).

Simplifying the expression will give us the final numerical value of the induced emf in the coil.

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The one that would prevent a person from naturalization becoming a United States citizen is: Pierre and his parents were born in another country. He is unable to speak or read English. Option B is Correct.

This is because one of the requirements for naturalization is the ability to speak, read, and write basic English. Since Pierre cannot do this, he would face difficulty in becoming a U.S. citizen through naturalization.

Due to his extensive interest in French politics, he frequently writes about it on social media. Pierre immigrated internationally.

Transnational migration is the movement of individuals who are connected to one another through social networks that cross international borders. There are economic and political linkages in addition to social ones.

Transnational migrants work, pray, and express their political ideas all across the world rather than in a single nation-state. Some will create strong foundations in their new nation, maintain close ties with their home nation, and join global religious and political organisations.

Dual nationals who live in both countries and Cuban Americans who moved to the United States but maintained ties to Cuba are two prominent examples of cross-border migration.

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A floating object on top of pond water would stay afloat due to buoyancy.

When an object is placed on top of a liquid, such as pond water, it experiences an upward force called buoyancy. This force is exerted by the liquid and is equal to the weight of the liquid displaced by the object. As long as the buoyant force is greater than or equal to the weight of the object, the object will float. This occurs because the density of the object is lower than the density of the liquid, allowing it to displace a volume of liquid greater than its own weight. As a result, the floating object will remain on the surface of the pond water.

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Answer:

You pull on the oars. By the third law, the oars push back on your hands, but that’s irrelevant to the motion of the boat. The other end of each oar (the blade) pushes against the water. By the third law, the water pushes back on the oars, pushing the boat forward.

Answer:

6.9 m/s

Explanation:

Answer:

The school is 3.40 meters tall.

Explanation:

You need to equations to solve this question. You need to know the time it takes to reach the ground and the time it takes for the two observers to hear it. The distance in both cases is the same, so the two conditions can be equated to each other.

Equations.

d = the height of the buildings

a is the acceleration due to gravity and is a constant 9.8i1 m/s^2

t1 is the time it takes to hit the ground

The initial velocity = 0 because the rock was dropped

Equation One

d = vi*t + 1/2 a t^2

Equation Two

d = v * t2

v is the velocity of sound

t2 is the time it takes for the sound to come back from hitting the ground.

d is the height of the school

Solution

vi*t + 1/2 a t1 ^2 = v * t2

t2 = 0.81 - t1

The times are separate, but they add up to 0.81 so

t1 I+ t2 = 0.81

t2 = 0.81 - t1

Rewrite the equation putting in the givens. Remember vi = 0

1/2 9.81  t1^2 = 340 * (0.81 - t1)        Remove the brackets

4.91* t1^2 = 275.4 - 340 t1               Transfer the right side to the left

4.91*t1^2 + 340t1 - 275.4 = 0           Use the quadratic formula to solve

a = 4.91

b = 240

c = -275.4

t1 = (-240 +/- sqrt(240^2 - 4*4.91*-275.4))/(2*4.91)

t1 = .8007 = 0.80

t1 + t2 = 0.81

0.80 + t2 = 0.81 - 0.80

t2 = 0.01

What you have found is the time it takes for the sound to come back to the two observers which is 0.01 seconds

d(height of school) = 340 * 0.01 = 3.4 meters

Answer:

If you hear thunder and then see lightning at almost the same time, this means that the lightning was likely close by. Thunder is the sound created by lightning, which is the discharge of energy between two clouds or between a cloud and the ground. Because sound travels much slower than light, it takes longer for the thunder to be heard, which is why we usually hear thunder after seeing a flash of lightning. This indicates that the lightning was very close in proximity and that you should be aware of the potential danger of an impending thunderstorm.

Answer:

Static friction prevents the motion of an object while sliding friction is a type of frictional motion between two surfaces in contact.

Explanation:

Answer:

1 gm

Explanation:

.05 g/cm^3   *  20 cm^3 =   1 gm

At 0.9 cm from the toroid's center, there is a 0.053 T magnetic field present.

the details provided;

The toroid's inner radius is 1.3 cm (0.013 m) and

its outer radius is 2.6 cm (0.026 m).

There are 1080 revolutions in the toroid.

carries a current of 2.1.

The following formula is used to compute the magnetic field at a distance of 1.95 cm from the toroid's center:

B= (μNI)/2\(\pi\)R

B=(4\(\pi\)*\(10^{-7}\))*(1080)*(2.1)/2\(\pi\)*0.0195

B=0.023 T.

The magnetic field is the area in which a magnet produces its magnetic effects. To describe how the magnetic force is dispersed in the area around and inside something magnetic in nature, we utilize the magnetic field as a tool.

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Answer:

transverse

Explanation:

Answer:

Transverse wave is the correct answer, the person above me is correct!

~Hope this helps! :)

Option (B) is the best choice in light of the stated statement. The Moon's orbital plane is inclined toward the ecliptic plane by around 5°.

The Moon will finish moving away from the planet at present rate of separation in around 15 billion years, according to calculations of the development of the Earth/Moon system. In around 6 to 7 billion years, our Sun is predicted to enter the Red Giant phase.

According to Newton's first law of motion, an item in motion will continue to move in a straight path if no force is applied to it. But since the Moon is subject to gravity, it deviates from the route that it would normally take.

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Answer:

because the Earth rotates, circulating air is deflected. Instead of circulating in a straight pattern, the air deflects toward the right in the Northern Hemisphere and toward the left in the Southern Hemisphere, resulting in curved paths. This deflection is called the Coriolis effect.

Answer:

Explanation:Digestive juices secreted by various organs such as salivary glands in the mouth, stomach, liver and pancreas help in the process of digestion of food. Saliva secreted by the salivary glands in the mouth aids in the breakdown of starch present in the food to simple sugar

Answer:

Object stop moving when the force which is friction that acts to resist sliding between two touch-ing surfaces is not present

Answer:

See below ~

Explanation:

Newton's 1st Law of Motion : "An object in motion (or rest) will stay in motion (or rest) unless acted upon by an unbalanced force.

Answer:

A. They can transfer energy through a vacuum

C. They vibrate in two directions that are perpendicular to each other

D. They radiate outward in all directions

Explanation:

A statement (A), a statement (C), and a statement (D) are correct because electromagnetic waves can only transfer energy through the vacuum.

The waves that are related to both electricity and magnetism are known as electromagnetic (EM) waves. These waves are made up of time-varying electric and magnetic fields that travel over space.

The correct statements are:

Thus, a statement (A), a statement (C), and a statement (D) are correct because electromagnetic waves can only transfer energy through the vacuum.

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Answer:

the spring would be a constant of 10.5 m

The magnitude of the magnetic field at the location of the charge due to the current-carrying wire is given as B = μI/2πr.

A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials.

A moving charge in a magnetic field experiences a force perpendicular to its own velocity and to the magnetic field.

The magnitude of the magnetic field at the location of the charge due to the current-carrying wire is calculated as follows;

B = μI/2πr

where;

Thus, the magnitude of the magnetic field at the location of the charge due to the current-carrying wire is given as B = μI/2πr.

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Answer:That only applies to highly polished surfaces, eg mirrors.

If you take a high quality laser (ie with low divergence) and aim it at a wall, you can see the spot where the laser beam reaches the wall from anywhere with a direct line-of-sight to the spot where the laser beam reaches the wall. This due to micro imperfections on the surface of the wall. At a microscopic level, the wall surface is very rough and pointing in all directions.

As to why, a beam of light bounces of a highly polished surface, I can only surmise that it is essentially due to kinematics, ie the only force opposing the light beam is normal to the surface, hence there no forces along the reflective surface. Since there are no forces along the reflective surface, the speed component of light along the reflective surface remains unchanged. However, on the plane perpendicular to the reflective surface the, the light photons bounce off at the same speed at which the hit the reflective surface because the mass of the reflective surface is much much much larger than the mass of the photons, which means that the reflective surface won’t move at all. Since conservation of momentum requires that momentum after the collision be the same as the momentum before the collision then the only way for that to happen is if the velocity of the photon perpendicular to the reflective surface is of exactly the same magnitude but in the opposite direction. Vector resolution of the speed component of the reflected beam means that the angle of reflection must be the same as the angle of incidence.

Explanation:

The angle of attack is approximately 4 degrees.

A more detailed explanation of the answer.

To find the angle of attack for a NACA 4415 airfoil with a 2m chord in an airstream with a velocity of 50 m/s and a lift per unit span of 1,595 N, follow these steps:

1. Calculate the dynamic pressure (q):
q = 0.5 * ρ * V^2
where ρ is the air density at standard sea-level conditions (1.225 kg/m³) and V is the airstream velocity (50 m/s).

q = 0.5 * 1.225 * (50)^2 = 1,531.25 N/m²

2. Calculate the lift coefficient (Cl):
Lift per unit span (L') = Cl * q * chord (c)
1,595 N = Cl * 1,531.25 N/m² * 2m

Now, solve for Cl:
Cl = 1,595 / (1,531.25 * 2) = 0.5208

3. Refer to a NACA 4415 lift coefficient vs angle of attack graph or data table to determine the angle of attack corresponding to the calculated Cl value. Since the Cl value is 0.5208, the angle of attack is approximately 4 degrees.

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