A 15W fluorescent light bulb uses operates for 30 minutes and produces 20kJ of light energy, what is the percent efficiency of the light bulb? Show work.

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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Answer:

the second one

Explanation:

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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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Given data

height (h) = 25 m ,

velocity (v) = ?

we know that,

                     v²-u² = 2as

                      initial velocity (u) = 0,

                                                a = g = 9.8 m/s ,

                  Now the equation becomes,

                                     v² = 2 × g × h

                                         = 2 × 9.8 × 25

                                     v² = 490.5

                                     v = √490.5

                                    v = 22.1 m/s

Therefore answer is C , i.e., 22 m/s (If you like this procedure, give me brainiest)

Answer:

c

Explanation:

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.

B. model; it is the model of the sun

Answer: B

Explanation: a light bulb

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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Answer:

Gravity pulls objects toward Earth.

The rate of acceleration due to gravity is 9.8 m/s2.

Weight on Earth’s surface is a result of gravity’s pull.

Explanation:

these are the answers for e2020

Gravity is a fundamental force that gives weight to objects and causes freefall. On Earth, it also causes the ocean tides and affects time, making it pass slower closer to Earth's surface. In our universe, it plays a vital role in the dynamics of celestial bodies.

Gravity is a force of attraction that exists between any two masses, any two bodies, any two particles. It is mathematically described as: F = G *(m1*m2)/r^2 where F is the force of attraction between the two bodies, m1 and m2 are the two masses, r is the distance between the centers of the two masses and G is the gravitational constant.

On Earth, gravity gives weight to physical objects and causes the ocean tides. The force of Earth's gravity comes from the object's mass and the acceleration due to gravity, which is approximately 9.8 m/s^2 at sea level. When an object is in freefall, the only force acting upon it is gravity.

Gravity also affects time and space, causing time to pass more slowly closer to the surface of the Earth compared to further away. This concept is known as time dilation. In essence, gravity is a crucial force that plays a key role in the structure and lifecycle of planets and the orbital movement of celestial bodies.

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Answer:

(C) (see image of it attached)

Answer: circuit C

Explanation:

A DC voltage source supplies current in single direction. It is represented by alternate small and big straight lines.

An Ac voltage source supplies alternating current i.e. the current changes direction.

In the given circuit diagrams, only circuit C has a DC voltage source.

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

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.

63x1/2 + 65x0.3 + 67x1/5

=

64.4 average atomic mass

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

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%.

Answer:

Explanation:

first notice some physics; the mass of the ball (projectiles) is not germane. A 2 ton elephant launched at U = 28 m/s will go just as high, which is H = U^2/2g = 28^2/(2*9.8) = 40 meters.

The process of calculating the height reached by the ball involves equating the kinetic energy at the beginning of its trajectory with the potential energy at its highest point. By assigning values to the mass and initial speed variables in the equation (1/2 × m × v² = m×g×h), we find that the ball reaches a height of approximately 40 meters.

The subject of this question is physics, specifically a concept known as projectile motion. When Dave throws the tennis ball straight up into the air, the ball has initial kinetic energy but loses this energy as it gains potential energy, causing it to decelerate until it reaches its maximum height and momentarily stops before falling back down.

We can calculate the height using the formula for kinetic and potential energy. The initial kinetic energy (K.E) is given by the formula 1/2 × m × v², where m is the mass of the ball and v is the initial velocity of the ball. The potential energy (P.E) at the highest point is given by the formula m×g×h, where g is the acceleration due to gravity and h is the height. Therefore, the initial kinetic energy equals the maximum potential energy (1/2 × m × v² = m×g×h)

Since we know the mass (0.07 kg) of the ball and the speed (28 m/s) at which it was thrown, we can substitute these values into the equation to calculate the maximum height, h.

So, h = (1/2 × m × v²) / (m×g) = (1/2 × 0.07 kg × (28 m/s)²) / ( 0.07 kg × 9.8 m/s²). Therefore, the tennis ball will reach a height of approximately 40 meters.

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Answer:

Force  = 375 Newton or 375 kg m/s²

Explanation:

Force is the product of the mass of a body and the acceleration . Force is usually the push or pull of the mass of an object that is accompanied by the motion(acceleration). Force is a vector quantity  because it has both magnitude and direction. Example is when you throw a ball you apply a push, with the mass of the ball and the acceleration computed you can calculate the force applied .

Mathematically, force can be represented as

Force = mass × acceleration

F = ma

Force is measured in Newton or Kg m/s²

From the question;

mass  = 125 kg

acceleration = 3 m/s²

Force = 125 × 3 = 375 Newton or 375 kg m/s²

Force  = 375 Newton or 375 kg m/s²

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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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.

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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The number-labels don't show in the picture, so we don't know the number of the correct one.

The correct path is the one shown in the upper-right panel.  The path of the light beam forms the shape of the letter ' V ', with the point at the bottom, down on the book.

p=m•v=25•4=100 kg•m/s

As asked in question the momentum of the 25kg object moving at 4 m/s is 100 kilogram meters per second (kg·m/s).

To calculate the momentum of a 25-kilogram object moving at a speed of 4 meters per second, you can use the formula for momentum:

Momentum (p) = Mass (m) × Velocity (v)

Where:

Mass (m) is 25 kilograms (kg)

Velocity (v) is 4 meters per second (m/s)

Now, plug in these values:

Momentum (p) = 25 kg × 4 m/s = 100 kg·m/s

So, the momentum of the 25kg object moving at 4 m/s is 100 kilogram meters per second (kg·m/s).

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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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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.

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 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.

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

m1=3600 kg

m2=900 kg

G1=m1g

G2=m2g

G2/G1=m2g/m1g=m2/m1=3600/900=4

Answer:

The answer is B. 1/4

Explanation:

Both objects are on the same planet therefore gravity acts the same upon each.

Object C mass is 3600 kg.

Object D mass is 900 kg.

The mass of Object C is 4 times the mass of Object D. (3600 / 900=4)

The mass of Object D is 1/4 times the mass of Object C. (900 / 3600=1/4)

Mass is proportional to weight. The more the mass, the more the weight.

Object C is heavier. Object D is lighter.

It's asking for the weight ratio of Object D to Object C therefore 900 is divided by 3600 to come to 1/4.

Answer:

1.6 kg

Step-by-step Solution:

Since Force = mass × acceleration we have:

F = 8N

a= 5 m/s^2

m = ?

By plugging the values above into F=ma we obtain:

[tex]F=ma\\\\8=m(5)\\\\\frac{8}{5}=\frac{m(5)}{5}\\\\m=\frac{8}{5}=1.6[/tex]

Therefore, the Chromebook has a mass of 1.6 kilograms.

Using Newton's second law of motion, we estimate that the mass of the chromebook would be 1.6 kg if it is thrown with a force of 8N and an acceleration of 5m/s².

In order to find the mass of the chromebook, we can use Newton's second law of motion, which states that Force equals Mass times Acceleration (F = ma).

If Mrs. Reichelt throws the chromebook with a force of 8N and it accelerates at 5m/s2, we can rearrange the equation as follows: Mass equals Force divided by Acceleration (m = F/a).

m = 8N / 5m/s2

As a result, the mass of the chromebook is 1.6 kg.

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Milli- ... thousandth ... 0.001

Centi- ... hundredth ... 0.01

Micro- ... millionth ... 0.000 001

Kilo- ... thousand ... 1,000

Mega- ... million ... 1,000,000