Which of the following best describes what causes the phases of the moon?
A. The alignment of the sun, Earth and moon (I think it's this one)
B. The speed of the moon around the Earth C. The speed of the Earth around the sun D. The alignment of the planets

Final answer:

The minimum time a player must wait before touching the basketball after it has been tossed straight up by the referee is approximately 0.469 seconds, which is the time taken for the ball to reach its maximum height.

Explanation:

The student is asking about the time it takes for an object (a basketball in this case) to reach its maximum height when thrown vertically upwards. This situation can be analyzed using the equations of motion under constant acceleration due to gravity. Since gravity will be slowing down the ball until it stops and starts falling, we can use the initial velocity and the acceleration due to gravity to find the time taken to reach the maximum height.

Using the equation v = u + at, where v is the final velocity (0 m/s at the maximum height), u is the initial upward velocity (4.6 m/s), a is the acceleration due to gravity (-9.8 [tex]m/s^2[/tex]), and t is the time in seconds, we can solve for t. Here, the negative sign for acceleration indicates that gravity is acting opposite to the direction of the initial velocity.

Substituting the known values, we get:

0 = 4.6 m/s - (9.8 [tex]m/s^2[/tex] × t)

t = 4.6 m/s / 9.8 [tex]m/s^2[/tex]

t = 0.469 seconds (rounded to three decimal places)

This is the time for the ball to reach the peak of its motion. To find the minimum time that a player must wait before touching the ball, we just consider this time, since the ball starts to fall immediately after reaching its maximum height.

Answer: The correct answer is 0.11 Hz.

Explanation:

The relation between frequency of the wave and time period is as follows;

[tex]f=\frac{1}{T}[/tex]

Here, f is the frequency of the wave and T is the time period.

Here, the frequency is inversely proportional to the time period.

It is given in the problem that a wave has a wavelength of 45 meters and a period of 9.0 seconds.

Calculate the frequency of the wave.

[tex]f=\frac{1}{T}[/tex]

Put T= 9 s.

[tex]f=\frac{1}{9}[/tex]

f=0.11 Hz

Therefore, the frequency of the wave is 0.11 Hz.

Answer:

[tex]W_{tot}=W_{1}+W_{2}=mgh_{2}=7.55[J][/tex]

Explanation:

The work done on an object is the scalar product between force and displacement. So we can write the work:

[tex]W=F\cdot d=Fd[/tex]

In our case F and d are parallels then we have a common product of their magnitudes.

Now, the total work will be the sum these two works:

Let's recall that the force in this problem is just the weight of the book. F=m*g

Finally, the total work will be the sum of W₁ and W₂.

[tex]W_{tot}=W_{1}+W_{2}=mgh_{2}=2.2*9.81*0.35=7.55[J][/tex]

I hope it helps you!

To calculate the work done on the book, the student librarian must use the formula W = mgh for each segment of lifting the book vertically. The total work done is the sum of the work for lifting the book to 1.25 m and then to 0.35 m. The horizontal distance carried does not contribute to work against gravity.

The work done on the book by the student librarian can be calculated by considering the work done against gravity to lift the book to different heights. The distance carried horizontally does not involve work against gravity under the assumption that there is no horizontal force like friction opposing the motion. The work done to lift the book from the floor to 1.25 m can be calculated using the formula W = mgh, where m is the mass of the book, g is the acceleration due to gravity (approximately 9.8 m/s2), and h is the height.

The initial lift is W = 2.2 kg × 9.8 m/s2 × 1.25 m. When placing the book from the carried position to a shelf at 0.35 m height, the work done is W = 2.2 kg × 9.8 m/s2 × 0.35 m since the vertical displacement is from 1.25 m to 0.35 m, not the full 1.25 m again.

The total work done on the book is the sum of these two amounts of work. Please note that the gravitational constant (g) could be given or assumed in this context. The exact value used may vary slightly depending on the context of the problem.

The correct balanced equation is N₂ + 3H₂ ⇒ 2NH3, which represents the chemical reaction where one mole of nitrogen reacts with three moles of hydrogen to produce two moles of ammonia. The coefficients reflect the simplest whole number ratio for the stoichiometry of the reaction.

The balanced chemical equation among the given options is N₂ (g) + 3H₂ (g) ⇒ 2NH3 (g). This reflects the stoichiometry of the reaction where each nitrogen molecule (N₂) reacts with three hydrogen molecules (3H₂) to form two molecules of ammonia (2NH3). The coefficients indicate the mole ratio needed for the reaction to occur, which is also demonstrated through models showing the combination of gas volumes following the reaction stoichiometry. Alternatively, the equation 3N2 + 9H2 → 6NH3 is not balanced at the simplest ratio. After dividing each coefficient by the greatest common factor (3), the previous balanced equation is obtained, which is the preferred simplified form. This balanced equation can be used to establish an equilibrium in a sealed container, showcasing the relationship between changes in the concentrations of the species involved, as determined by the stoichiometry.

Final answer:

The balanced chemical equation for the synthesis of ammonia from nitrogen and hydrogen is N₂ (g) + 3H₂ (g) → 2NH3 (g), which follows the stoichiometric ratio of 1:3:2.

Explanation:

The balanced equation for the reaction between nitrogen (N₂) and hydrogen (H₂) to form ammonia (NH₃) is N₂ (g) + 3H₂ (g) → 2NH3 (g). This equation satisfies the law of conservation of mass, meaning that the number of atoms for each element is the same on both the reactant and product sides of the equation. One mole of nitrogen gas reacts with three moles of hydrogen gas to yield two moles of ammonia gas, indicating a mole ratio of 1:3:2, respectively. The equation shows ammonia molecules are produced from nitrogen and hydrogen molecules in a 2:3 ratio, reflecting the stoichiometry of the reaction.

Fleming's right-hand rule (for generators) shows the direction of induced current when a conductor moves in a magnetic field. It can be used to determine the direction of current in a generator's windings.

When a conductor such as a wire attached to a circuit moves through a magnetic field, an electric current is induced in the wire due to Faraday's law of induction. The current in the wire can have two possible directions. Fleming's right-hand rule gives which direction the current flows

The right hand is held with the thumb, first finger and second finger mutually perpendicular to each other (at right angles.

The car was initially traveling at approximately 22.02 m/s.

To solve this problem, we can break it down into horizontal and vertical components. Let's call the initial velocity of the car 'v.'

The car's horizontal velocity after the collision is given by its initial velocity multiplied by the cosine of the angle, which is 28 m/s * cos(37°). The truck's horizontal velocity after the collision is 0 m/s since it was initially stationary.

Since no horizontal forces act on the system after the collision, the momentum in the horizontal direction is conserved. Thus, the sum of the initial flat rates of the car and the truck must equal the final horizontal velocity. Therefore, m * v = m * (28 m/s * cos(37°)), where 'm' represents the mass of the car and the truck.

If we divide both sides of the equation by 'm', we get v = 28 m/s * cos(37°). Evaluating this expression, we find v ≈ 22.02 m/s.

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So,option A)Change in the fullback's momentum:779 kg·m/s,B)Change in the defensive tackle's momentum: -779 kg·m/s,C)Defensive tackle's original momentum:-779 kg·m/s (opposite direction),D)The original speed of the defensive tackle:6.09 m/s.

Understanding Momentum and Collision:

A) Change in the fullback's momentum: Momentum is the product of mass and velocity. For the fullback running at 8.2 m/s with a mass of 95 kg, his initial momentum was 95 kg × 8.2 m/s = 779 kg·m/s. After the collision, since they stop, the fullback's speed is 0 m/s, giving a final momentum of 0 kg·m/s. Therefore, the change in momentum is 779 kg·m/s - 0 kg·m/s = 779 kg·m/s.

B) Change in the defensive tackle's momentum: The defensive tackle has mass 128 kg and final speed 0 m/s. Since we are not given the initial velocity, we cannot calculate the change directly; however, by conservation of momentum, the change will be equal and opposite to the fullback's, which is -779 kg·m/s.

C) Defensive tackle's original momentum: As mentioned above, the change in momentum is the negative of the fullback's, so if the fullback's momentum decreased by 779 kg·m/s, the tackle's momentum increased by this amount, meaning it was -779 kg·m/s (opposite direction).

D) The original speed of the defensive tackle: To find the original speed, we take the original momentum (from C) and divide by the tackle's mass. This gives us -779 kg·m/s ÷ 128 kg = -6.09 m/s. The negative indicates that he was moving in the opposite direction to the fullback.

Note that 'negative' here is used to indicate direction in one-dimensional motion, and the actual speed is just the absolute value, 6.09 m/s.

Answer:

s = - 4 cos 4t + 2t + 6.

Explanation:

a = dv/dt = 16 cos 4t ,

dv = 16 cos 4t dt

integrating on both sides

v = 16 x sin 4t /4 + c

    = 4 sin 4t + c

when t = 0 , v = 2

2 = 0 + c

c = 2

v = 4 sin 4t + 2

ds/dt = 4 sin 4t + 2

ds = ( 4 sin 4t + 2) dt

integrating on both sides

s = - 4 cos 4t/4 + 2t + k

    = - cos 4t + 2t + k

when t = 0 s = 5

5 =  -1 + 0 + k

k = 6

s = - 4 cos 4t + 2t + 6.

Ans.

Answer:

-1.176 m/s²

Explanation:

Given:

weight of aluminium block is w = 20.0 N

frictional force, f = 2.4 N

final velocity, v = 0

distance covered, d = 10 m

From Newton's second equation of motion,

F = ma

where, m is the mass and a is the acceleration.

mass of the block, m g = 20.0 N

m = 2.04 kg

The block is brought to rest by friction force:

f =- m a

⇒ 2.4 N = -(2.04 kg)(a)

⇒a = -1.176 m/s²

Answer:

it is cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc

Explanation:

becai=use i know

Answer : Distance, d=6.98 × 10⁷ Km

Explanation :

Given that,

Mass of the sun, m₁ = 1.99 × 10³⁰ kg

Mass of Mercury, m₂ = 3.30 × 10²³ kg

Gravitational force between the sun and mercury, F = 8.99 × 10²¹ N

According to Universal law of gravitation,

[tex]F=G\dfrac{m_1m_2}{d^2}[/tex]

d is the distance of mercury from the sun

[tex]d=\sqrt{\dfrac{Gm_1m_2}{F}}[/tex]

[tex]d=\sqrt{\dfrac{6.67\times 10^{-11}\times 1.99\times {30}\times 3.30\times 10^{23}}{8.99\times 10^{21}}}[/tex]

[tex]d=\sqrt{4.87\times 10^{21}} m[/tex]

[tex]d=6.98\times 10^{10}\ m[/tex]

or

[tex]d=6.98\times 10^{7}\ Km[/tex]

So, mercury is [tex]6.98\times 10^{7}\ Km[/tex] far from the sun.

The forces that two charged particles exert on each other are equal in magnitude and opposite in direction, so F2 = -F1, where F2 is the force Q1 exerts on Q2, and F1 is the force Q2 exerts on Q1.

When two charged particles Q1 and Q2, with Q2 being 5 times the charge of Q1, are separated by a distance r, the force they exert on each other can be determined using Coulomb's law. According to Coulomb's law, the magnitude of the force between two point charges is directly proportional to the product of the charges and inversely proportional to the square of the distance between them. Since Q2 is 5 times Q1, we have Q2 = 5Q1. However, the force that Q2 exerts on Q1 (F1) is equal in magnitude and opposite in direction to the force that Q1 exerts on Q2 (F2) due to Newton's third law of motion, which states that every action has an equal and opposite reaction.

Therefore, the correct answer to the question is F2 = -F1. This indicates that the forces are equal in magnitude but opposite in direction. The negative sign simply denotes the opposite direction of the force, not that the magnitude of the force is negative.

According to Coulomb's law and Newton's third law, two charged particles exert forces of equal magnitude but opposite directions on each other, so if Q2 = 5Q1, then F2 = -F1.

When considering two charged particles exerting forces on each other, it's important to apply Coulomb's law, which states that the force between two point charges is directly proportional to the product of the magnitudes of the charges and inversely proportional to the square of the distance between them. Additionally, Newton's third law of motion tells us that for every action, there is an equal and opposite reaction. This means that if a charge Q2 exerts a force F1 on Q1, then Q1 must exert a force F2 of equal magnitude but in the opposite direction on Q2.

Given that Q2 = 5Q1 and they are a distance r apart, Coulomb's law would indicate that the magnitudes of the forces each charge exerts on the other (F1 and F2) would be equal. Thus, the correct answer is F2 = -F1, where the negative sign indicates the forces have opposite directions.

Answer:

The answer is: B. boiling.

Explanation:

The value of the melting and boiling points are affected by the value of the atmospheric pressure.

The Celsius degree is the unit corresponding to the melting and boiling temperatures of water at 1 atm pressure. Celsius: Melting 0 ℃, Boil 100 ℃.

When a food is frozen at normal atmospheric pressure, its temperature drops to 0 ° C, at which time the water begins to turn into ice.

Normally, the atmospheric pressure that exists at sea level is taken as a reference. There it takes a value of 1 atmosphere.

Therefore, although the pressure is 1 atmosphere for all processes, the one that needs more temperature is the Boiling, which is 100 ° C.

The answer is: B. boiling.

Answer:

2. B. energy

3. D.kinetic energy

4. C. chemical

5. A.68.1 percent

6. A.chemical energy into thermal energy

7. D.mechanical energy

Explanation:

2. Energy is  the ability of matter to produce work in the form of movement, light, heat, etc.

3.  The kinetic energy of a body is that energy it possesses due to its movement.

4 .Chemical energy is the energy stored in the bonds of chemical compounds (atoms and molecules).

5. Efficiency can be calculated as (128J/188J)*100= 68%

6. Chemical energy is defined in item 4 and thermal energy is a type of energy that bodies possess when exposed to the effect of heat. It is precisely what produces that the atoms that make up the molecules are in constant motion either moving or vibrating.

7. Mechanical energy is the energy that bodies present because of their movement (kinetic energy), and their situation with respect to another body, usually the earth.

All your selected answers are correct. The ability to do work is energy, a person jogging has kinetic energy, energy in food is chemical, the rake has 68.1 percent efficiency, natural gas heating water is a chemical to thermal energy transformation process, and motion and position of an object relate to mechanical energy.

Yes, you are correct with your answers. The ability to do work or cause change is indeed called B.energy. A person jogging demonstrates D.kinetic energy as they are in motion. The type of energy available in food is C.chemical energy which is stored and can be transformed into other energy forms our body needs. With the work done raking leaves, if Dan does 188.0 J of work and the rake itself does 128.0 J of work then the efficiency of the rake would be (128.0 / 188.0) * 100 = 68.1 percent, hence, it is A.68.1 percent. The transformation of energy taking place when natural gas is used to heat water is A. Chemical energy into thermal energy. Finally, the energy associated with the motion and position of an object falls under D. mechanical energy, although if considering only the motion aspect, it is indeed A. Kinetic energy.

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The key difference between a mercury and an aneroid barometer is that an aneroid barometer does not use mercury to measure pressure changes, instead utilizing a mechanical metal chamber that expands and contracts in response to atmospheric pressure.

An aneroid barometer measures pressure changes without the need of mercury, which is how it differs from a mercury barometer. A mercury barometer consists of a glass tube filled with mercury, measuring atmospheric pressure by the height of the mercury column. In contrast, an aneroid barometer uses a sealed, evacuated and flexible metal chamber known as an aneroid cell, which expands and contracts with atmospheric pressure changes. These mechanical movements are then translated into pressure readings.

Comparatively speaking, the statement 'The aneroid barometer does not use mercury to measure pressure changes' is the correct difference between the two types of barometers. Therefore, the answer to the student's question is option (c).

Barometers using water are impractical because they would need to be extremely tall, over 30 feet, due to water's lower density compared to mercury, which allows for a more compact design in mercury barometers.

Answer:

C.the moon at apogee coming between Earth and the sun along a straight line

Explanation:

As we know that Earth rotate about the sun in elliptical orbit as one of the planet.

While moon rotate about the Earth similarly as one of the satellite around it

now when moon, Sun and Earth all lie in the same line such that position of moon is between the positions of Sun and Earth then in this case the light coming from sun is totally bounded by the position of moon

This situation of moon is known as Solar Eclipse

so here during the motion if the moon at apogee coming between Earth and the sun along a straight line then it is the most likely cause of annular solar eclipse.

The force exerted by the chin-up bar on the person's body depends on the acceleration. At certain times, the force is 0 N, while at other times it can be calculated using the formula Force = Mass x Acceleration.

The force exerted by the chin-up bar on the person's body can be calculated using the equation:

Force = Mass x Acceleration

At t = 0s, the person's body is at rest, so the acceleration is 0. Therefore, the force exerted by the bar is 0 N.

At t = 0.5s, the person's body is moving upward with a constant speed. Since the velocity is constant, the acceleration is 0 and the force exerted by the bar is 0 N.

At t = 1.1s, the person's body is moving upward with an increasing speed. The acceleration can be calculated using the change in velocity over time, and then substituted into the force equation to find the force exerted by the bar.

At t = 1.6s, the person's body is moving upward with a decreasing speed. The acceleration can be calculated using the change in velocity over time, and then substituted into the force equation to find the force exerted by the bar.

Answer:

Columns

Explanation:

The groups are arranged in columns on the Periodic Table.

Final answer:

The work done by a person who exerted a force of 500 Newtons to move a full wheelbarrow over a distance of 30 meters is 15000 Joules.

Explanation:

If a person exerted a force of 500 Newtons (F = 500 N) to move a full wheelbarrow over a distance of 30 meters (d = 30 m), the work done can be calculated using the formula:

Work (W) = Force (F) × Distance (d)

Plugging in the given values, we get:

W = (500 N) × (30 m) = 15000 Joules (J)

The work done is therefore 15000 Joules, which demonstrates the transfer of energy through force applied over a distance.

Answer:

[tex]v = 3.28 m/s[/tex]

Explanation:

At the top position of the arc if ball continue in its circular path then we can say that tension force must be zero at that position for the minimum value of the speed.

So we will have

[tex]T + mg = \frac{mv^2}{R}[/tex]

so if minimum speed is required to complete the circle T = 0

[tex]0 + mg = \frac{mv^2}{R}[/tex]

so we will have

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

again we will have

[tex]v = \sqrt{1.10\times 9.81}[/tex]

[tex]v = 3.28 m/s[/tex]