What causes different colors to appear in the sky?

Time period of simple pendulum is given by formula

[tex]T = 2\pi \sqrt{\frac{L}{g}}[/tex]

here

L = length of pendulum

g = acceleration due to gravity

now as per formula we can see that time period is directly proportional to the square root of the length.

So in order to increase the time period we can increase its length

so correct answer would be

b. by making the string longer

Answer:

by making the string longer

Explanation:

A scalar quantity is one in which there is no direction given.

30 Lbs would be the answer, since there is no indicator of direction.

Given:

Time taken: 3.5 hrs

Speed: 120mi/HR

Now we know that

distance = speed x time

Substituting the given values in the above formula we get

Distance= 120mi/hr x 3 hrs

Distance = 360 mi= 579.36 Km

The speed is the distance covered by an object at a particular time. The distance between the Platform 9 and Hogwarts is 360 miles.

The speed is the distance covered by an object at a particular time. Therefore, it is the ratio of distance and time.

Speed = Distance Covered / Time taken

Given that it takes 3.5 hours for the Hogwarts Express, moving at a speed of 120 mi/hr, to make it from Platform 9 to Hogwarts. Therefore, we can write the given quantities as,

Speed of the Hogwarts Express = 120 miles per hour

Time taken = 3 hours

Now, the distance between the Platform 9 and Hogwarts can be written as,

Speed = Distance / Time

120 miles per hour = Distance / 3 hours

Distance = 120 miles per hour × 3 hours

Distance = 360 miles

Hence, the distance between the Platform 9 and Hogwarts is 360 miles.

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Final answer:

Air masses are large bodies of air with uniform conditions formed in specific regions, which travel and influence weather by redistributing energy across the Earth's surface. They contribute to balancing the global climate by moving heat from warmer to cooler areas.

Explanation:

Air masses are vast bodies of air that encompass thousands of square miles, with uniform temperature, humidity, and pressure characteristics. Air masses form in source regions typically characterized by low relief and calm winds which allow for the air to acquire the traits of the Earth's surface beneath it. After a period of about 3 to 5 days, an equilibrium is established between the air mass and the source region, via radiative processes and vertical mixing of heat.

High-pressure regions are ideal for the genesis of air masses as the subsiding air promotes homogeneity. Once formed, air masses travel and as they move, they can modify the weather conditions of the regions they pass over. For instance, a maritime tropical (mT) air mass which originates over a warm ocean, if it passes over a colder current, will get chilled and become more stable, while a continental polar (cP) air mass might become less stable if it moves over a warmer region.

Energy redistribution on Earth's surface is a critical function of air masses. The movement of air masses, driven by winds and air currents, helps in transferring heat from warmer regions of the planet to cooler regions, balancing the global energy budget. Without this process, the world would experience extreme temperatures that could threaten the viability of ecosystems and human societies.

The continual movement and interaction of different air masses lead to the formation of weather fronts, and consequently, climatic events like precipitation and storms. This dynamic behavior contributes significantly to the global climate patterns observed.

Answer:

Student’s(50 kg) gravitational potential energy if the cliff is 80 m high = 39.2 kJ

Explanation:

   Potential energy is given by the expression, PE =mgh, m is the mass, g is the acceleration due to gravity value and h is the height.

 Here mass of student, m = 50 kilogram

           Height of cliff , h = 80 meter

           Acceleration due to gravity = [tex]9.8m/s^2[/tex]

 Potential energy, PE = 50 * 9.8 * 80 = 39200 J

                                    = 39.2 kJ

Student’s(50 kg) gravitational potential energy if the cliff is 80 m high = 39.2 kJ

If his velocity is constant, then there is zero net force on him . . . any force acting on him is exactly canceled by an equal force in the opposite direction.

In the case of a sky-diver, the force of gravity on him (his weight, downward) is exactly canceled by the force of air resistance upward.

The net force on him is zero.  If the net force on him were not zero, then his velocity  wouldn't be constant. He would be accelerated in the direction of the net force.

the answer is c another magnet can be attracted or repelled because they have north and south sides

Answer: Option (C) is the correct answer.

Explanation:

A magnet will only be attracted by another magnet as each magnet contains opposite poles. These poles are north pole and south pole.

Hence, like poles are repel each other whereas opposite poles are attracted towards each other.

Therefore, when a magnet comes in contact with a copper wire then there will be attraction between them.

On the other hand, if south pole of a magnet comes in contact with the north pole of another magnet then a force of attraction will occur between them.

Due to this both the magnets get attracted towards each other. But when south pole of a magnet comes in contact with the south pole of another magnet then force of repulsion will occur.

Thus, we can conclude that another magnet will be attracted to or repelled by a magnet.

consider east-west direction along X-axis  and north-south direction along Y-axis

[tex]V_{ra}[/tex] = velocity of migrating robin relative to air = 12 j m/s

(where "j" is unit vector in Y-direction)

[tex]V_{ag}[/tex] = velocity of air relative to ground = 6.3 i m/s

(where "i" is unit vector in X-direction)

[tex]V_{rg}[/tex] = velocity of migrating robin relative to ground = ?

using the equation

[tex]V_{rg}[/tex] = [tex]V_{ra}[/tex] + [tex]V_{ag}[/tex]

[tex]V_{rg}[/tex] = 12 j + 6.3 i

[tex]V_{rg}[/tex] = 6.3 i + 12 j

magnitude : sqrt((6.3)² + (12)²) = 13.6 m/s

direction : tan⁻¹(12/6.3) = 62.3 deg north of east

here in this type of collision we can use momentum conservation

[tex]P_{1i} + P_{2i} = P_{1f} + P_{2f}[/tex]

here we know that

[tex]m_1 = 122 kg[/tex]

[tex]v_{1i} = 13 m/s[/tex]

[tex]v_{2i} = -17 m/s[/tex]

[tex]v_{1f} = v_{2f} = - 3.5 m/s[/tex]

now by above equation of momentum conservation

[tex]122* 13 + m_2*(-17) = 122*(-3.5) + m_2*(-3.5)[/tex]

[tex]1586  - 17*m_2 = - 427 - 3.5* m_2[/tex]

[tex]1586 + 427 = (17 - 3.5)*m_2[/tex]

[tex]2013 = 13.5*m_2[/tex]

[tex]m_2 = \frac{2013}{13.5}[/tex]

[tex]m_2 = 149 kg[/tex]

so mass of the player 2 will be approx 149 kg

That is true, i think.

Answer:

True

Explanation:

Answer with Explanation:

Atom=Smallest Particle present on earth

Subatomic Particle=Smaller than Atom(Electron +Proton)

Electron = -vely Charged Particle

Proton =+vely Charged Particle

In J.J Thompson Model of Atom , which is called Plum Pudding model ,Electrons and Protons that is Subatomic particles were uniformly Distributed inside the Nucleus of Atom.

But Rutherford Contradicted Thompson by saying that, Protons are fixed inside the nucleus and Electrons are moving in Elliptical path around the nucleus like the planets around the sun.This Model is Known as Planetary Model.

Work done on the crate is given by

[tex]W = Fd cos\theta[/tex]

here we have

[tex]F = 142 N[/tex]

[tex]d = 6.1 m[/tex]

[tex]\theta = 37 degree[/tex]

now we have

[tex]W = Fdcos37[/tex]

[tex]W = 142 * 6.1 * cos37[/tex]

[tex]W = 691.8 J[/tex]

So it require 691.8 J work to slide the block across horizontal floor

Acceleration =  speed / time

speed = v= 30m    time = t 9s

a  = v/ t

  30m/ 9s

= 3.4ms⁻¹

The hockey puck is decelerating at an approximate rate of 0.37 m/s² based on the given distance covered and time taken for the puck to come to a stop.

In this case the hockey puck covered a distance of 30 m and came to rest in 9 seconds. This is a clear case of constant deceleration which can be calculated using the formula for constant acceleration: a = (v - u) / t. Here, t = time = 9 s, u = initial velocity (which we don't know), and v = final velocity = 0 m/s (since the puck comes to rest). The only unknown here is the initial velocity. However, since we know the total distance travelled by the puck (d = 30 m) and the time taken we can utilise the second equation of motion: d = ut + 0.5at². By substituting the known values and simplifying, we arrive at the equation 30 = 9u indicating that u = 3.33 m/s (approx).

With the initial velocity determined as 3.33 m/s, we can calculate acceleration, i.e., deceleration as a = (v - u) / t = (0 - 3.33) / 9, which comes out as -0.37 m/s². The negative sign indicates deceleration (or slowing down). So the constant deceleration of the hockey puck is approximately 0.37 m/s² in magnitude.

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kinetic energy is what causes objects to move, and the absence of kinetic energy causes energy to stay still. It is also important to remember that energy is neither created or destroyed, and is constantly being reused.

The lava flowed through low-lying valleys and over the smaller Cascade Mountain Range. As it reached the ocean shore, it sank down into the soft sediments, cooling and hardening into thick black basalt.

Hope I Helped

they can be called polar covalents

Polar molecules are hydrophillic, So you can say hydrophillic (loves water)

Answer:

It take the bullet 0.64 seconds to hit the ground.

Explanation;

 We have equation of motion , [tex]s= ut+\frac{1}{2} at^2[/tex], s is the displacement, u is the initial velocity, a is the acceleration and t is the time.

Here we need to consider only vertical motion of bullet.

Initial velocity = 0 m/s, Displacement = 1.98 m, acceleration = acceleration due to gravity = [tex]9.8m/s^2[/tex], we need to find time taken

Substituting

   [tex]1.98= 0*t+\frac{1}{2} *9.8*t^2\\ \\ 4.9t^2=1.98\\ \\ t^2=0.404\\ \\ t=0.64 seconds[/tex]

   It take the bullet 0.64 seconds to hit the ground.

Level of sound is related to intensity by this equation

[tex]L = 10 Log \frac{I}{I_o}[/tex]

given that

L = 85 dB

also we know that

[tex]I_o = 10^{-12} W/m^2[/tex]

now we have

[tex]85 = 10 Log \frac{I}{10^{-12}}[/tex]

By solving above equation

[tex]I = 10^{8.5} * 10^{-12}[/tex]

[tex]I = 3.16 * 10^{-4} W/m^2[/tex]

now above is the intensity due to two firecrackers and if we wish to find the sound level of one firecracker then we will find its half level intensity

[tex]I_1 = \frac{I}{2}[/tex]

[tex]I_1 = 1.58 * 10^{-4}[/tex]

now again by above formula

[tex]L = 10 Log \frac{1.58 * 10^{-4}}{10^{-12}}[/tex]

[tex]L = 82 dB[/tex]

Before coming into a conclusion, first we have to understand Einstein's mass energy equivalence theory.

As per this theory ,mass and energy are inter convertible.This theory is mathematically written as-

E=mc^2. Where m is the mass and c is the velocity.

So, when some amount of mass is lost, equivalent amount of energy is produced as per this theory.

As per law of conservation of energy, the total energy of the universe is always constant.Energy is neither created nor destroyed.It only changes from one form to another.

In case of sun,the energy is produced due to fusion reaction.In this type of reaction there will be mass defect .Due to this loss of mass, equivalent amount of energy is produced which comes into earth in the form of radiations.

Here the law of conservation of energy is not violated .Before the fusion reaction,the energy was trapped inside the atoms .When the reaction was initiated, correspondingly same amount of energy is produced due to mass defect ,but the total energy is always constant.

Hence,it is also in accordance with the law of conservation of energy.

Hence,the correct answer to the question is D i.e all the energy that reaches Earth from the Sun was originally contained within the Sun’s atoms.

The atomic emission spectra of a sodium atom on earth and of a sodium atom in the sun would be the same.

When atoms of sodium get excited they move to a higher level and when they move back to the ground level, they emit photons.

Thus the emitted energy of photon depends only on the atom of the sodium (element) and is independent of the atmosphere where it is .Since we are comparing the emission spectra of the same element sodium it is the same on both earth and sun.

Neither would move.

Hope this helps.

The question is unclear regarding the boat's velocity. Is it 20 m/s south relative to the water, or relative to the earth? (It is a river, after all...)

There's also the possibility that the boat's velocity relative to the river is 0. Take the south direction to be negative and north to be positive, and denote by [tex]v_{A/B}[/tex] the velocity of a body A relative to a body B. Under these conditions,

[tex]v_{B/E}=v_{B/W}+v_{W/E}\iff-20\,\dfrac{\mathrm m}{\mathrm s}=0+-20\,\dfrac{\mathrm m}{\mathrm s}[/tex]

(B for boat, E for earth, W for water) so that the passenger's velocity relative to the earth is

[tex]v_{P/E}=v_{P/B}+v_{B/W}+v_{W/E}[/tex]

(P for passenger)

[tex]v_{P/E}=10\,\dfrac{\mathrm m}{\mathrm s}+0-20\,\dfrac{\mathrm m}{\mathrm s}=-10\,\dfrac{\mathrm m}{\mathrm s}[/tex]

or 10 m/s south.

Answer:

Deceleration of the car is 2[tex]\frac{m}{s^{2} }[/tex].

Explanation:

Given:

initial speed = 12 m/s

final speed = 8 m/s

time = 2 s

To find:

acceleration = ?

Formula used:

According to first kinematic equation:

v = u + a t

Where, v = final speed

u = initial speed

t = time

a = acceleration

Solution:

According to first kinematic equation:

v = u + a t

Where, v = final speed

u = initial speed

t = time

a = acceleration

8 = 12 + 2 a

-4 = 2 a

a = -2 [tex]\frac{m}{s^{2} }[/tex]

The negative sign implies that it is deceleration. Thus, deceleration of the car is 2[tex]\frac{m}{s^{2} }[/tex].

Answer:

Acceleration value of car = -2 [tex]m/s^2[/tex]

Explanation:

 We have equation of motion, v = u + at, where v is the final velocity, u is the initial velocity, a is the acceleration and t is the time taken.

Here a car is traveling at 12 m/s, so initial velocity = 12 m/s

After 2 seconds the speed drops to 8 m/s, so final velocity = 8 m/s

Time taken = 2 seconds

Substituting

        8 = 12 + a * 2

         2a = -4

         a = -2 [tex]m/s^2[/tex]

 Acceleration value of car = -2 [tex]m/s^2[/tex]

Answer:

There is an arrow up for the air resistance and an arrow down for gravity. The arrow up is shorter than the arrow down.

Explanation:

So in the free-body diagram you have to draw all the forces that are acting over some body.

In this case when the skydiver is falling down there are only 2 forces acting on him, the gravitational force and the air resistance, therefore in the free-body diagram should be 2 arrows, now we have to determinate the direction of this arrows, so like the gravitational force is pulling the skydiver down (towards to earth) the arrow for this one should be down, and for the air resistance as it's trying to stop skydiver's fall it's direction it's upwards. now for the length of the arrows we have to look in which direction is the skydiver speeding up, in the question it says that the skydiver is speeding up down so the bigger arrow should be downwards too.

Answer:

Battery

Explanation:

A battery has the most potential energy, due to its chemical potential energy.

Answer: The correct option is 3.5m/s.

Explanation: In the question, conservation of energy is taking place which means that the energy is getting transferred from one form to another form.

Here, elastic potential energy of the spring is getting converted to the kinetic energy of the block.

Mathematically,

[tex]\frac{1}{2}kx^2=\frac{1}{2}mv^2[/tex]

where, k = spring constant = 56N/m

x = compression of extension of spring = 0.75m

m = Mass of the block = 2.5kg

v = velocity of the block = ? m/s

Putting values in above equation, we get:

[tex]\frac{1}{2}\times 56\times (0.75)^2=\frac{1}{2}\times 2.5\times v^2\\\\v=3.54m/s[/tex]

Hence, the block will move at a speed of 3.5m/s

The velocity of the block after the spring is released is approximately 13 m/s.

To find the velocity of the block after the spring is released, we can use the principle of conservation of mechanical energy. The potential energy stored in the spring will be converted into the kinetic energy of the block as it moves.

The potential energy (U) stored in a spring is given by the equation:

[tex]\[ U = \frac{1}{2} k x^2 \][/tex]

where k is the spring constant and x is the compression of the spring.

 For this problem:

[tex]\[ k = 56 \, \text{N/m} \][/tex]

[tex]\[ x = 0.75 \, \text{m} \][/tex]

So the potential energy stored in the spring is:

[tex]\[ U = \frac{1}{2} (56 \, \text{N/m}) (0.75 \, \text{m})^2 \][/tex]

[tex]\[ U = \frac{1}{2} (56 \, \text{N/m}) (0.5625 \, \text{m}^2) \][/tex]

[tex]\[ U = 15.4 \, \text{J} \][/tex]

This potential energy will be converted into the kinetic energy (K) of the block, which is given by:

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

where m  is the mass of the block and  v  is its velocity.

The mass of the block m is 2.5 kg, so we have:

[tex]\[ \frac{1}{2} m v^2 = U \][/tex]

[tex]\[ \frac{1}{2} (2.5 \, \text{kg}) v^2 = 15.4 \, \text{J} \][/tex]

[tex]\[ (1.25 \, \text{kg}) v^2 = 15.4 \, \text{J} \][/tex]

[tex]\[ v^2 = \frac{15.4 \, \text{J}}{1.25 \, \text{kg}} \][/tex]

[tex]\[ v^2 = 12.32 \, \text{m}^2/\text{s}^2 \][/tex]

[tex]\[ v = \sqrt{12.32 \, \text{m}^2/\text{s}^2} \][/tex]

[tex]\[ v \ = 13 \, \text{m/s} \][/tex]

To answer this question, we must use the equation for the volumetric expansion of gases at constant pressure. This equation is given by:

[tex]V=V_{0}(1 + \alpha(T_{2}-T_{1}))[/tex]

We know:

[tex]V_{0}[/tex] is the initial volume [tex]= 0.5 m ^ 3[/tex]

ΔT is the temperature change = 45 ° -20 ° = 25 °

[tex]\alpha[/tex] is the coefficient of gas expansion and is equal to 1/273

Then the final volume of the gas is:

[tex]V=0.5*(1+\frac{1}{273}*25)[/tex]

[tex]V=0.546m^ 3[/tex]

force applied due to earth on the apple is given as

[tex]F = ma[/tex]

given that

m = 0.37 kg

a = 9.8 m/s^2

now we have

[tex]F = m*a[/tex]

[tex]F = 0.37* 9.8 = 3.63 N[/tex]

now as per Newton's III law equal and opposite force is applied on earth

so now we can find acceleration of Earth using same equation as we used above

[tex]F = ma[/tex]

here we know that

m = mass of earth

F = 3.63 N

[tex]3.63 = 5.98 * 10^{24} * a[/tex]

[tex]a = \frac{3.63}{5.98 * 10^{24}[/tex]

[tex]a = 6.1 * 10^{-25} m/s^2[/tex]

so acceleration of earth is very small and given by above value

According to Newton's third law, the apple and the Earth exert equal and opposite forces upon each other when the apple is in free-fall. The force that the apple exerts on the Earth is its weight (0.37 kg * 9.8 m/s^2 = 3.626 N), and this is the same magnitude of force that the Earth applies on the apple, causing it to accelerate towards the Earth's surface.

Indeed, according to Newton's third law, for every action, there is an equal and opposite reaction. This principle applies to the scenario of an apple falling towards the earth's surface. When you drop the apple, its weight, or the force due to gravity, accelerates it at 9.8 m/s^2, towards the earth. Conversely, the apple exerts an equivalent force back towards earth. However, due to earth's significantly larger mass, the acceleration it experiences as a result of this force isn't noticeable.

Now, let's clarify the concept of this force exerted by the apple. Weight can be computed as the product of mass and gravity (w=mg). In this case, the mass is 0.37 kg and gravity is 9.8 m/s^2, thus the weight of the apple is 3.626 N. This value represents the force that the apple exerts on Earth when it's in free fall, which is also the force that Earth exerts on the apple, causing it to accelerate downwards.

The magnitudes of these forces are equal, aligning with Newton's third law. Yet, the direction of the forces are opposite. When Earth pulls the apple downwards, the apple simultaneously pulls Earth upwards with the same magnitude of force.

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