Determine the moment about the origin O of the force F = 4i - 3j + 5k that acts at a point A. Assume that the position vector of A is (a) r = 3i - 6j + 5k, (b) r = i - 4j - 2k, (c) r = -8i + 6j -8k

Astronomers know that pulsating variable stars are actually expanding and contracting in diameter with the help of the Doppler effects of light waves.

The Doppler effect is a phenomenon that occurs when two objects move closer or farther apart, increasing (or decreasing) the frequency of sound, light, or other waves.

The Doppler effect is applicable to sound waves as well as light waves,

Thus, the Doppler effect on sound may be compared to the color of light waves, which helps astronomers to know about pulsating variable stars actually expanding and contracting in diameter.

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Answer: 2.5 ML

Explanation:

10 ÷ 10 = 1

25 ÷ 10 = 2.5

The volume of 1 coin is 2.5 ML

The area would be 13.1429 Meter².

Answer:

\(\boxed {Area = 13.14 m^{2}}\)

Explanation:

Formula applied :

\(\boxed {Area = \frac{Pressure}{Force}}\)

Given :

Solving :

They have a limited supply in nature, therefore if they are used excessively, they will become exhausted.

Today, we recognise that using fossil fuels has a negative impact on the environment. Fossil fuels produce and utilise local pollutants, and their continued use permanently alters the temperature of our entire world.

Wastes from combustion sources are those that result from carbon pollution (i.e., coal, oil, natural gas). Included in this are all ash and particles taken out of the flue gas.

The fossile fuel is limited in nature. So, it should not waste energy from fossil fuels.

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The potential difference is 4,477.61 volts.

To determine the potential difference (V), we can use the formula V = W/Q, where W represents the energy in joules and Q is the charge in coulombs.

Given:

Energy (W) = 300 millijoules = 300 × 10\(^(-3)\) J

Charge (Q) = 67 microcoulombs = 67 × 10\(^(-6)\)C

Substituting these values into the formula:

V = (300 × 10\(^(-3)\)J) / (67 × 10\(^(-6)\)C)

Calculating the potential difference:

V = 300 × 10\(^(-3)\)J / 67 × 10\(^(-6)\)C

V = 4,477.61 volts

Therefore, the potential difference required to move a charge of 67 microcoulombs with an energy of 300 millijoules is approximately 4,477.61 volts.

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The kinetic energy of the electron accelerated by a 30 kV source is approximately 4.8 x 10^(-14) Joules.

Voltage (V) = 30 kV = 30,000 volts

Charge of an electron (e) = \(1.6 x 10^(-19) C\)

Calculating the potential energy -

P = e x  V

An object's motion gives it kinetic energy, which is a type of energy. It is described as the amount of effort required to accelerate a body of a specific mass from rest to its specified velocity. As Potential energy is equal to kinetic energy, therefore calculating the kinetic energy:

Potential Energy = Kinetic Energy = e x V

Substituting the value -

\(= (1.6 x 10^(-19) C) x (30,000 V)\)

\(= 4.8 x 10^(-14) J\)

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Answer:

the height of the building is 0.8 m.

Explanation:

Given;

mass of the object, m = 250 g = 0.25 kg

final velocity of the object, v = 4 m/s

let the height of the building = h

Apply the principle of conservation of energy to determine the height of the building;

¹/₂mv² = mgh

¹/₂v² = gh

\(h = \frac{v^2}{2g} \\\\h = \frac{4 ^2}{2 \times 10} \\\\h = 0.8 \ m\)

Therefore, the height of the building is 0.8 m.

Answer:

Th ball

Explanation:

Answer:

A I think hope it helps!!

Option a: if two hypotheses fit the facts equally well, choose the one with fewer assumptions.

Occam's razor states that principle of problem solving is that entities should not multiply more than necessary

Occam's Razor is the process of gathering information to make the search for the truth easier. In science, it gets rid of all assumptions that have no bearing on the predictions of the hypothesis. If you have several hypotheses that could explain an observation, it is usually best to start with the simplest one.

Occam's Razor is often at the root of a paradigm shift, where an established theory is replaced by a simpler alternative that also fits the data. For example, Ptolemy's epicycles were replaced by a simpler theory that explained the data without multiplying the elements.

Therefore Option (a) is correct.

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When an object spins counterclockwise in the plane of the screen and its rate of rotation is slowing down, the correct statements are: (b) Its angular velocity vector points into the page, and its angular acceleration vector points out of the page.

This is because the angular velocity vector points in the direction of the rotation, which in this case is counterclockwise and into the page.

The angular acceleration vector points opposite to the angular velocity, causing the rotation to slow down, and thus it points out of the page.

Therefore, (b) Its angular velocity vector points into the page, and its angular acceleration vector points out of the page is the correct answer.

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Complete question :

Question 30 1 pts An object spins counterclockwise in the plane of the screen, and its rate of rotation is slowing down. Which are true?

a. Its angular velocity vector points out of the page, and its angular acceleration vector points into the page.

b. Its angular velocity vector points into the page, and its angular acceleration vector points out of the page.

c. Both its angular velocity and angular acceleration vectors point out of the page.

d. Both its angular velocity and angular acceleration vectors point into the page.

e. Its angular velocity vector points out of the page, and its angular acceleration vector points towards the axis of rotation (center of the rotation). Its angular velocity vector points into of the page, and its angular acceleration vector points towards the axis of rotation center of the rotation).

Hi there!

We know that there are TWO forces acting on the man.

We can express this in an equation. Let DOWN be NEGATIVE, and UP be POSITIVE.

\(F_{net} = N - F_g\)

Recall that a SCALE measures the NORMAL FORCE, NOT the WEIGHT. Therefore:

N = 700 N

W = 900 N

\(F_{net} = 700 - 900 \\\\F_{net} = -200N\)

Since downward is negative, the net force is acting DOWNWARD.

The primary distinction between gravitational and electric force is that the gravitational force is the force of attraction between two objects that have mass, whereas the electric force is the force of attraction or repulsion between two objects that have an electric charge.

The gravitational force is always attractive, while the electric force can be either repulsive or attractive. The gravitational force is a long-range force that follows an inverse-square law, which means that the force decreases as the distance between the two objects increases. Meanwhile, the electric force can be either attractive or repulsive, and it follows an inverse-square law too.

However, it's considerably stronger than the gravitational force.The gravitational force is always present between any two objects with mass, whereas the electric force can only be seen between charged particles. The gravitational force is much weaker than the electric force; the force that two charged particles produce can be thousands of times stronger than the gravitational force between the two objects.However, gravity has its own set of unique features, such as its ability to bend the path of light and to warp space-time itself.

Gravitational force is the most fundamental force that governs the behavior of the universe at large distances. It is a force that can only attract and can never repel. Therefore, the gravitational force is a vital force that helps to keep planets and stars in orbit.

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Answer:

A

Explanation:

Answer:

Distance divided by time

Explanation:

Answer:

True

Explanation:

An object which moves in the negative direction has a negative velocity. If the object is slowing down then its acceleration vector is directed in the opposite direction as its motion (in this case, a positive acceleration).

Answer:

0.25 J

Explanation:

Answer:

1.46755 Joules

Explanation:

Applying,

E = 1/2ke²......................... Equation 1

Where E = Elastic potential energy of the spring, k = spring constant, e = extension

From the question,

Gieven: k = 559 N/m, e = (0.14-0.07) meters = 0.07 meters

Substitute these values into equation 1

E = 1/2(599×0.07²)

E = 2.9351/2

E = 1.46755 Joules

A pendulum bob with a mass of 0.15 kg and a speed of 3 m/s has a kinetic energy at the low point of its swing of 0.675 J.

Kinetic energy is the energy that an item has as a function of motion. A force must be applied to an object in to accelerate it. We must engage considerable efforts in order to apply a force. After the task is finished, energy is transferred to the item, which then moves at a new, constant speed.

For calculation:

kinetic energy at low point,

kinetic energy = mass in kg / velocity in m/s

now,

putting the value in given formula,

kinetic energy = 0.15 / 33

                         =0.675J

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The work done on the cart by the spring is equal to its change in kinetic energy. There is no loss due to friction.

According to the work-energy principle, the work done on an object is equal to its change in kinetic energy. In the case of a cart attached to a spring, when the spring is compressed and then released, it applies a force to the cart and does work on it, causing the cart to accelerate and gain kinetic energy.

The amount of work done by the spring is given by the formula W = (1/2)kx^2, where k is the spring constant and x is the displacement of the spring from its equilibrium position.If there is no friction present, then all the work done by the spring is converted into the kinetic energy of the cart. Therefore, the work done on the cart by the spring is equal to its change in kinetic energy.

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Answer:

a

Explanation:

occurs when the crest of one wave meets the trough of another wave as they travel from two different points in the same direction and at the same frequency

The fraction of light from the Sun intercepted and reflected by the Earth is approximately 4.26 x 10⁻⁵.

To calculate the fraction of light from the Sun intercepted and reflected by the Earth, we need to compare the cross-section of the Earth to the area of a sphere centered on the Sun with a radius equal to the radius of Earth's orbit.

The cross-section of the Earth can be calculated as the area of a circle with radius REarth, which is option (c) R Earth.

The area of a sphere centered on the Sun with a radius r is given by 4πr², where r is the radius of the Earth's orbit. Therefore, the area of the sphere centered on the Sun with a radius equal to the radius of Earth's orbit is 4π(149.6 x 10⁶ km)²= 2.83 x 10²³ m².

The ratio of the cross-section of the Earth to the area of the sphere is A1/A2 = πREarth² / 4πr² = (REarth/r)². Using the radius of Earth's orbit in meters, r = 149.6 x 10⁹ m, and the radius of Earth, REarth = 6,371 km = 6.371 x 10⁶ m, we get A1/A2 = (6.371 x 10⁶ m / 149.6 x 10⁹ m)² = 4.26 x 10⁻⁵.

Therefore, by calculating we can say that the fraction of light is approximately 4.26 x 10⁻⁵.

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Answer:

A. 1st law.

Explanation:

Newton's first law of motion states that, an object or body will continue to be at rest or experience a uniform motion in a straight line at constant speed provided there's no action of an external force. Thus, unless compelled to change its state by an external force, a body will continue to be at rest or experience a uniform motion in a straight line.

The Newton's first law of motion is also known as the law of inertia; which is the tendency of a body to be at rest unless acted upon by an external force.

In this scenario, you are standing in a subway train and the train suddenly stops but your body continues to move forward. This is in accordance with Newton's first law of motion.

Hence, the sudden stoppage of the train generates a force which acts on the body thereby causing the passenger to tip or move forward.

Answer:

The lifeguard should run approximately 17.752 meters along the shore, before, jumping in the water

Explanation:

The given parameters are;

The rate at which the lifeguard runs = 5 m/s

The rate at which the lifeguard swims = 1 m/s

The horizontal distance of the child from the lifeguard = 30 meters along the shore

The vertical distance of the child from the lifeguard = 60 meters along the shore

Let x represent the distance the lifeguard runs

We have;

The distance the lifeguard swims = √((30 - x)² + 60²)

Time = Distance/Speed  

The time the lifeguard runs = x/5

The time the lifeguard swims = √((30 - x)² + 60²)/1

The total time = √((30 - x)² + 60²) + x/5

The minimum time is given by finding the derivative and equating the result to zero, as follows;

Using an online application, we have;

d(√((30 - x)² + 60²) + x/5)/dx = 1/5 - (30 - x)/(√((30 - x)² + 60²)) = 0

Which gives;

1/5 - (30 - x)/(√(x² - 60·x + 4500) = 0

(30 - x)/(√(x² - 60·x + 4500)) = 1/5

5×(30 - x) = √(x² - 60·x + 4500)

We square both sides to get;

(5×(30 - x))² = (x² - 60·x + 4500)

(5×(30 - x))² - (x² - 60·x + 4500) = 0

25·x² - 1500·x + 22500 - x² + 60·x - 4500 = 0

24·x² - 1440·x + 18000 = 0

Dividing n=by 24 gives;

24/24·x² - 1440/24·x + 18000/24 = 0

x² - 60·x + 750 = 0

By the quadratic formula, we have;

x = (60 ± √((-60)² - 4×1×750))/(2 × 1) =

Using an online application, we have;

x = (60 ± 10·√6)/(2)

x = 30 + 5·√6 or x = 30 - 5·√6

x ≈ 42.25 m and x ≈ 17.752 m

At x = 42.25

Time = √((30 - 42.247)² + 60²) + 42.247/5 ≈ 69.69 seconds

At x = 17.75

Time = √((30 - 17.752)² + 60²) + 17.752/5 ≈ 64.79 seconds

Therefore, the route with the shortest time is when the lifeguard runs approximately 17.752 meters (rounded to three decimal places) along the shore, before, diving in the water

Answer:

Convection cells

Explanation:

As the cold air moves away from poles, it begins to warm up. This warm air now becomes lighter and the pressure drops significantly at 60° N and 60° south latitude. The air from poles further gushes into these belts because the low pressure created. Thus, convection cells are formed because this rise and fall of air in circular pattern.

Hence, the name given is convection cells.

Answer:

I would say the answer is A... but I'm not so sure ....

Answer:

18.78 m/s.

Explanation:

From the question given above, the following data were obtained:

Mass (m) = 50 kg

Initial velocity (u) = 0 m/s

Height (h) of cliff = 18 m

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

Final velocity (v) =?

The velocity with which the diver reach the water can be obtained as follow:

v² = u² + 2gh

v² = 0² + (2 × 9.8 × 18

v² = 0 + 352.8

v² = 352.8

Take the square root of both side

v = √352.8

v = 18.78 m/s

Thus, the diver will reach the water with a velocity of 18.78 m/s.

Answer:

a is the correct answer

from the formula of wave length=v/f

therefore f= v/wave length

these implies f= 345/4.15 = 83.1hertz