Complete the following statement: today, the standard unit of time is defined in terms of

Answer:

Scientific theories

Explanation:

Answer:

c

Explanation:

To solve for F in the conversion formula, multiply both sides by 9/5 followed by adding 32 to isolate F. When converting 20 degrees Celsius using the formula, the result is 68 degrees Fahrenheit.

Part 1: Solving the equation for F

To solve the equation C = 5/9 (F - 32) for F, perform the following steps:

Multiply both sides by 9/5 to get rid of the fraction on the right side: 9/5 × C = F - 32.

Add 32 to both sides of the equation to isolate F on one side: 9/5 × C + 32 = F.

Part 2: Converting 20 degrees Celsius to Fahrenheit

To find out how many degrees Fahrenheit 20 degrees Celsius is, plug 20 into the rearranged equation:

F = (9/5) × 20 + 32.

Therefore, F = 36 + 32 = 68 degrees Fahrenheit.

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.

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.

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:

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.

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.

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:

[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]

Using the equations of motion, the length of the runway required for the 727 jet to take off can be determined. By calculating the acceleration and using the distance formula, we find that the runway must be at least 44.7039 meters long.

To determine the length of the runway required for the 727 jet to take off, we can use the equations of motion.

Therefore, the runway must be at least 44.7039 meters long for the 727 jet to take off.

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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It's 200 on Edmentum

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.

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:

Columns

Explanation:

The groups are arranged in columns on the Periodic Table.

Answer: Option (A) is the correct answer.

Explanation:

A seesaw is a simple machine which has a long board and on a fixed part it is balanced in the middle.

For example, a seesaw on which children play in the park is balanced at the middle on a fixed point so that children sitting on both the sides can move up and down with the same force.

Thus, we can conclude that seesaw is a simple machine type of machine.

Seesaw is classified as a simple machine. The correct option is( A)

A seesaw is categorized as a basic machine since it functions using the levering principle. One of the six traditional simple machines, together with the inclined plane, wedge, screw, wheel and axle, and pulley is the lever.

The lever in the case of a seesaw is a long, rigid beam that pivots on a fulcrum. A back-and-forth motion is possible because of the effort put in on one end of the seesaw, which forces the other end to rise and fall.

Therefore, The correct option is ( A)

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The frequency of a wave is the inverse of time period. Hence, its unit is s⁻¹ which is equivalent to Hz unit. The standard unit of frequency is Hz.

Frequency of an event is the number of cycles of that event per unit time. For a wave frequency is the number of wave cycles per second. Hence, frequency is the inverse of time period.

Frequency of a wave is directly proportional to the energy of the wave and inversely proportional to the wavelength. Hence, the high frequency waves are shorter waves.

The unit of frequency is called Hertz (Hz) which is equal to s⁻¹ because, it is the frequency is inverse of the time period of the wave. Therefore, frequency is measured in units called Hertz.

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