Which of these is studied using science?

a. thirteen is an unlucky number
b. finding a four leaf clover is lucky
c. breaking a mirror brings bad weather
d. sudden fall in air pressure affects weather

Answer:

A) Nuclear fusion

Explanation:

Nuclear fusion is a process that occurs when two light nuclei fuse together forming a heavier nucleus. In such a process, the mass of the final nucleus is slightly lower than the total mass of the initial nuclei, so part of the mass is converted into energy, according to Einstein's equation:

[tex]E=mc^2[/tex]

where

E is the energy released in the process

m is the difference in mass between final products and initial nuclei

[tex]c=3.0\cdot 10^8 m/s[/tex] is the speed of light

Given the huge value of [tex]c^2[/tex], we see that in the process of nuclear fusion a tremendous amount of energy is released even for very small values of the mass, m.

Nuclear fusion occurs inside the core of the stars and it is the process responsible for the energy produced by the stars. The main process that occurs inside the core of a star is the fusion of two nuclei of hydrogen into a nucleus of helium.

Answer:

A) nuclear fusion

Explanation:

The reactions that occur in stars are nuclear fusion in which two lighter nuclei combine to give a heavier nucleus with release of enormous energy.

An acceleration unit needs a unit of length or distance on top and a unit of (time · time) on the bottom.  Let's go through the list:

- km/hr/s = (km) / (hr · sec) . . . Yes

- km/hr/hr  = (km) / (hr · hr) . . . Yes

- m/s² = (m) / (sec · sec) . . . Yes

- km/s  = (km) / (sec) . . . No . . . This is the only one that's NOT acceleration.  This one is actually a unit of speed .

- m/s/s = (m) / (s · s) . . . Yes

The correct answer is km/hr/hr. The units km/hr/hr represent acceleration in kilometers per hour per hour, which is not a valid unit for acceleration.

The correct answer is km/hr/hr. The units km/hr/hr represent acceleration in kilometers per hour per hour, which is not a valid unit for acceleration. Here's a breakdown of the other options:

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The output of a heat engine is always lower than its energy input due to the second law of thermodynamics, which posits an inevitable 'loss' in the conversion of heat to work. This is because systems move naturally towards a state of higher disorder or entropy and thus decrease the availability of energy for work. The relationship between heat, work, and energy elucidates this principle.

The output of energy from a heat engine is fundamentally related to the energy supplied to it considering the second law of thermodynamics. This law is expressed in two forms, firstly, heat transfers naturally from a hot body to a cooler one but not the reverse. Secondly, it is not possible to completely convert heat energy into work in a cyclical process returning the system to its original state.

In heat engines, a cyclical process frequently returns the engine to its original state. These engines, as indicated by the second form of the second law of thermodynamics, cannot attain a perfect conversion of heat into work. This is due to the overarching principle of entropy, which means systems naturally go towards a state of higher disorder, decreasing the availability of energy to be converted into work.

The precise relation between heat, work, and internal energy is exemplified in the first law of thermodynamics. It affirms the conservation of energy by declaring that any changes in a system's internal energy (U) will be equal to the heat transferred to the system (Q) minus any work done by it (W), in the equation ΔU = Q - W. Therefore, the energy output from a heat engine is always less than the energy input because of energy lost to the environment, largely due to the inherent inefficiencies of the heat-to-work conversion process and entropy increase.

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The output energy of a heat engine is less than the input energy due to the second law of thermodynamics. Efficiency is calculated as the work output divided by heat input, and is always less than 100% because some energy is lost as heat.

The output of energy from a heat engine is related to the energy put into it by the concept of efficiency, which is restricted by the second law of thermodynamics. This law, stated in terms of entropy, indicates that it is impossible to have a perfect conversion of heat into work; some energy will always be lost as heat to the surroundings. For example, if a heat engine performs 10.0 kJ of work with an 8.50 kJ heat transfer to the environment, the heat transferred into the engine (initial thermal energy input) is the sum of these two amounts, equaling 18.5 kJ. The efficiency (η) of the engine is calculated as the work done divided by the heat transferred into the engine, which in this case would be 10.0 kJ/18.5 kJ, resulting in an efficiency of approximately 54%.

To find speed with distance and time, you need to remember the speed formula:

Speed = distance ÷ time

So we need speed and we have the other two values, we can plug the values in:

Speed = 20 ÷ 2 = 10

The measurement for speed in this case is m/s (metres per second)

The answer would be 10mph

Answer: 2.3 m/s/s

Explanation:

The car is traveling at a constant speed of 12 m/s and after acceleration, the speed is 26 m/s so the acceleration of the car will be 2.33 m/s².

The ratio of velocity to time is referred to as acceleration. It is a vector quantity with SI unit m/s².

There are several types of acceleration :

According to the question,

The initial velocity of the car, (u) is given as 12 m/s,

The final velocity of the car, (v) is given as 26 m/s and,

The time, (t) is given as 6 seconds

Use the equation of motion,

v = u + at

26 = 12 + (a)6

a = 14/6

a = 2.33 m/s².

Hence, the acceleration of the car is 2.33 m/s².

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Answer: acceleration

                  i.e., a = g =9.81 m/s²  at sea level of the earth

Answer:

The girl threw the marshmallow with a speed  of 35.4 m/s.

Explanation:

Use the formula for the range of projectile motion:

[tex]R = \frac{v^2\cdot \sin2\theta}{g}[/tex]

with R the range or distance (92m), theta the elevation angle (67 degrees) and g the gravitational acceleration. The velocity can be determined from this as follows:

[tex]|v| = \sqrt{\frac{R\cdot g}{\sin 2 \theta}} = \sqrt{\frac{92m\cdot 9.8 \frac{m}{s^2}}{\sin 134^\circ}}=35.40\frac{m}{s}[/tex]

The girl threw the marshmallow with a speed  of 35.4 m/s, which is approximately 79 mph. No word on the boy's condition after the marshmallow's landing.

When your mass increases your weight on earth also increases

2- it also increases

When a person's mass increases on Earth, their weight also increases since weight is the gravitational force acting on mass. Mass does not change with location, while weight can vary with gravity's strength. An astronaut's mass is constant, but their weight decreases on the Moon due to lower gravity.

The relationship between mass and weight is a fundamental concept in physics. When your mass on Earth increases, your weight also increases. This is because weight is the force of gravity acting on an object's mass. Since gravity on Earth is essentially constant, an increase in mass results in a directly proportional increase in weight.

It is essential to understand that while mass is a measure of the quantity of matter in an object and does not change with location, weight is the gravitational force exerted on that mass and can vary with the strength of the gravitational field. On Earth, the acceleration due to gravity is approximately 9.80 m/s².

An example to illustrate this is comparing your weight on Earth to that on the Moon. If an astronaut traveled from Earth to the Moon, their mass would remain the same but their weight would decrease because the Moon's gravitational acceleration is only about one-sixth that of Earth's (1.67 m/s² compared to 9.80 m/s²).

1,  yeti hair is thick and strong

2, a warm blanket and a change of clothes

3, to circulate the heat around the house/room

Yeti products are designed to keep beverages at a desired temperature, which explains their popularity. The best way to warm up from the cold includes dressing in layers and consuming warm foods or beverages. Ceiling fans in winter help to redistribute warm air that rises, maintaining an even temperature in a room.

Yeti products are popular and useful because they are designed with advanced insulation technologies that maintain the temperature of liquids for an extended period. This makes them ideal for outdoor activities and preserving the temperature of beverages. To warm up when coming from the cold, it is effective to dress in layers, consume warm beverages or food, and engage in physical activity to generate body heat. People may turn on ceiling fans during winter while the heater is on to distribute warm air more evenly throughout a room, as warm air rises and can leave the lower parts of a room cooler without proper circulation.

Science encourages curiosity and questioning, which is foundational for inquiry-based learning. To answer questions using the scientific method, one would formulate a hypothesis, conduct experiments, observe results, and draw conclusions. This process allows scientists to develop models and make informed decisions based on evidence. In the context of temperature and heat, one might explore how materials affect thermal retention or the rate of cooling in substances, like in the example of adding cream to coffee and when to do so for keeping the coffee warmer.

The average speed would be 76 km/h. You get this by simply diving the distance by the time.

If a car traveled 190 kilometers in 2.5 hours then the average speed of the car in kilometers per hour would be

The total distance covered by any object per unit of time is known as speed. It depends only on the magnitude of the moving object. The unit of speed is a meter/second. The generally considered unit for speed is a meter per second.

The mathematical expression for speed is given by

speed = total distance /Total time

As given in the problem If a car traveled 190 kilometers in 2.5 hours then we have to find the average speed of the car in kilometers per hour,

The total distance covered by the car =  190 kilometers

the total time taken by the car = 2.5 hours

the average speed of the car = 190/2.5  kilometers/ hour

the average speed of the car = 76 kilometers/ hour

Thus, the average speed of the car would be 76 kilometers/ hour.

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W = work done by the spring on the toy car = 196 Joules

m = mass of the toy car = 2 kg

v₀ = initial velocity of the car when at rest = 0 m/s

v = final velocity of the car after spring does work on it = ?

According to work-change in kinetic energy, net work done on an object is same as the change in kinetic energy of the object . hence

Net work done = Final kinetic energy - initial kinetic energy

W = (0.5) m (v² - v₀²)

inserting the values

196 = (0.5) (2) (v² - (0)²)

v² = 196

v = sqrt(196)

v = 14 m/s

The final velocity of the toy cars is 14 m/s

Given data:

The mass of toy car is, m = 2 kg.

The work performed by the spring is, W = 196 J.

In the given problem, the work done by the spring provides the necessary kinetic energy to the toy car. Therefore, work -energy theorem can be applied.

According to work-energy theorem, the work done on an objects is equal to the change in kinetic energy of the object .So,

W = KE

Solving as,

[tex]W = \dfrac{1}{2} mv^{2} \\\\196=\dfrac{1}{2} \times 2 \times v^{2}\\v = 14 \;\rm m/s[/tex]

Thus, we can conclude that the final velocity of the toy cars is 14 m/s .

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The point goes to the service team.

Answer:

The ball will be considered as a good ball and point will be given to the serving team.

Explanation:

In volleyball if the ball touches the line then it will considered as a good ball and point will be given to the serving team. If the ball goes outside the line without touching any member of opposing team then it would be considered as a bad ball and point will be given to opposite team and so the service.

Position ' C ' is the middle of the swing.  That's where the weight is the lowest.

It's also the place where the weight is moving the fastest, so that means it's the place where the kinetic energy is greatest.

Answer:

At point C

Explanation:

The velocity of the pendulum is maximum at its mean position, i.e., at C.

Formula for Kinetic energy is given by

[tex]K = 1\div 2\times m\times v^{2}[/tex]

As velocity is maximum at C so kinetic energy is also maximum at C.

-- You start out.

-- You walk 20 m north.

-- Then you walk 5 m south.

-- Your displacement, relative to where you started from is 15 m north .

X

Hot air rises = it's less dense than cold air = falls

Answer: X

Explanation:

In the given diagram, air moves as a result of convection currents. The air at the bottom, near the space heater gets heated up. As temperature rises, the density of air reduces. It becomes less dense and rises up. The least dense is at W. As the air rises, it gets cooled and becomes more dense and heavier and thus, sinks down. The highest density of air would be at X.

a = (Vf - Vi) / t = (13.9 m/s - 0 m/s) / 10 s = 1.4 m/s^2

Answer:

Acceleration of the bus is 1.38 m/s^2

Explanation:

Given that,

Initial speed of the bus, u = 0 m/s (rest)

Final speed of the bus, v = 50 km/h

or v = 13.88 m/s

Time taken, t = 10 s

To find :

The magnitude of the acceleration of the car.

Solve :

Let a is the acceleration of the car. The rate of change of velocity is called the acceleration of the bus. Its formula is given by :

[tex]a=\dfrac{v-u}{t}[/tex]

[tex]a=\dfrac{(13.88-0)\ m/s}{10\ s}[/tex]

[tex]a=1.38\ m/s^2[/tex]

Therefore, the magnitude of the car's acceleration is 1.38 m/s^2.

It takes fossil fuels to form millions of years thats why they are regarded as non-renewable socrce of fuels

The period of the stoppers motion is 1.2 second. Hence, option (A) is correct.

Centripetal acceleration is a characteristic of an object's motion along a circular path. Centripetal acceleration applies to any item travelling in a circle with an acceleration vector pointing in the direction of the circle's center.

A centripetal acceleration occurs when you drive in a circle, and a centripetal acceleration also occurs when a satellite orbits the earth. Centripetal refers to being in the center.

Mass of the rubber stopper: m = 0.013 kg.

Length of the string: r = 0.93 meter.

Tension in the string is: T = 0.35 Newton.

Hence, centripetal acceleration of the rubber stopper: a = 0.35/0.013 m/s²

= 26.92 m/s²

Let the angular velocity is ω; then

ω²r = a

ω = √(26.92/0.93) rad/s

= 5.38 rad/second.

Hence, the period of the stoppers motion is = 2π/ω

= 2π/5.38 second

= 1.2 second.

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d 30 minutes a day , 5 days a week

Answer:

D. 30 minutes per day, 5 days a week

Explanation:

As per World Health Organization (WHO) physical activity includes the following :

- Leisure time physical activity like running

- Occupational work

- Household chores

- Sports

An adult (aged 18-64) should do at least 150 minutes of physical activity per week. That can be divided over 5 days a week as well with 30 minutes of physical activity per day.

Answer: Radiation.

In Radiation heat transfer, no particles are involved to transfer the energy unlike conduction and convection. This means that the energy transfer by radiation work when objects are not touching even in the space

1. We are wormed by sun, even though it is millions of kilometers away is the space.

2. Infrared camera give images even in dark, because they are detecting infrared light not the visible light.

Answer:

The net force is zero

Explanation:

When an object is falling, there are two forces acting on it:

- The force of gravity, which is equal to the weight of the object, which pushes the object downwards

- The air resistance, which acts against the motion of the object, so it pulls upward

While the magnitude of the force of gravity is constant, the magnitude of the air resistance increases as the velocity of the falling object increases: at some point of the motion, the air resistance becomes equal in magnitude to the force of gravity. At this point, the net force on the object becomes zero, and according to Newton's second law, the acceleration of the object becomes also zero:

[tex]F=ma[/tex]

But zero acceleration means that the velocity of the object is now constant: this is known as terminal velocity.

To push the child higher on the swing, you can apply Newton's Second Law of Motion. By exerting a greater force on them and pushing at the right moment, you can increase their height on the swing.

To push the child higher on the swing, you can apply Newton's Second Law of Motion. This law states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. To push the child higher, you need to exert a greater force on them by pushing with more strength or pushing for a longer time.

The force you apply to the child is the net force, which is the force pushing them forward minus the force of gravity pulling them down. By increasing the net force, you can increase the acceleration of the child and make them move higher on the swing.

Additionally, you can also push the child at the right moment to take advantage of the swing's motion. Pushing when the child is moving forward and upward can help increase their height on the swing.

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First law of thermodynamics:

Limitations of First law

II law of thermodynamics:

It states that "the total entropy of the system can never decrease over time"

It is strongly proved by two laws, they are

1. Kelvin-plank statement:

      He stated that "any engine does not give 100% efficiency". It violates the Perpetual motion of machine II kind(PMM-II).

2. Classius statement:

       It states that "Heat always flows from high temperature body to low temperature body, without aid of external energy".

         Also it stated that " Heat can also be transferred from low temperature body to high temperature body, by the aid of an external energy".

Applications of II law:

Refrigeration &Air conditioning, Heat transfer, I.C. engines, etc.

Answer:

The answer is D.

Explanation:

I just took the quiz.

B. model; it is the model of the sun

Answer: B

Explanation: a light bulb

Im not 100% sure but i think its bromine.

Hope this helps ^_^

Velocity = (distance covered in a direction) / (time to cover the distance)

Since the y-axis is position (distance), the speed at 3 seconds is the slope of the graph at 3 seconds, and NOT its y-value.

The slope is fairly easy to pick off, because the graph is so straight from 2 sec to 5 sec.  During that time, the distance shrinks by 10 meters (from 10m to zero).  So the slope of that whole piece of the graph is  (-10m) / (3 sec).

That's a slope of  (10/3 m/s) or 3.33 m/s .

In answer to the question, we can only give the speed at 3 sec, not the velocity, since we have no information about the direction of the motion.  Consequently, I would call the speed a positive number.  But it's not worth arguing about, so you should just select choice-A and not make a big scene.

The velocity at 3 seconds can't be determined accurately without additional information such as acceleration and the initial velocity. Velocity in physics depends on these additional factors, meaning a correct answer can't be given with the given information.

Without more information, it's impossible to accurately determine the velocity at 3 seconds. In physics, velocity is a measure of speed in a specific direction and it depends on acceleration, the initial velocity, and the time elapsed. Not having any of this additional information means we can't give a correct answer. As such, any of the choices (A, B, C, D, E) could be potentially correct depending on the circumstances of the object's movement.

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There are no statements that describe the Curies' work well on the list of choices you provided.

(And their name was "Curie", not "Cutie".)

there is  no answer choices

If they come in direct contact, then with certain restrictions, the neutral charge  will experience a transfer of 1/2 a charge from the positive body providing we're talking about a large enough charge that can be transferred.

So if one sphere starts with no charge and one with 6 * 10^-14 Q, if they touch,then each sphere will have a charge of 3*10^-14 Q which is still a pretty big charge.

According to Boyle-Mariotte:

p₁V₁=p₂V₂=>V₂=p₁V₁/p₂= 0.0024*101.70/ 84.16=0.0028 m³

Answer:

tim e (t) = 20 min.

            = 20 × 60 = 1200 s ,

Work ( W) = 4560000 J

                 = 4560 KJ ,

Determine:

                 Power output (P) = Work ÷ time

                                              = 4560 ÷  1200

                                            P  = 3.8 KW