Please help on this one?

Answer:

Paul B. MacCready, 81; inventor of human-powered aircraft, other innovations. Paul B. MacCready, the Caltech-trained scientist and inventor who created the Gossamer Condor -- the first successful human-powered airplane -- as well as other innovative aircraft, has died. He was 81.

Explanation:

Paul MacCready is credited with creating the first human-powered aircraft, the Gossamer Condor, which was able to follow a controlled, pre-determined course.

Paul MacCready is a renowned figure in the world of aviation. He is mainly credited with creating the first human-powered aircraft to fly a pre-determined course. This aircraft is recognized as the Gossamer Condor, a revolutionary aircraft design that not only was powered by a human but also had the ability to be controlled and maneuver in flight. MacCready's innovative work in aviation technology has greatly contributed to how we understand and approach the concept of flight in the modern day.

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Answer:

All this is due to atmospheric pressure (which decreases with height) and affects the boiling point of water. That is why for recipes that carry some liquid (cake or bread, for example) it is necessary to modify both the ingredients and the baking time.

To better understand this, let's begin by explaining that the boiling point of water at an atmospheric pressure at sea level is [tex]100\°C[/tex] and as the height increases and the atmospheric pressure decreases, this boiling point  will diminish, as well.

This means the water will not boil at the same temperature at different pressures, because at lower pressure the boiling temperature will be lower.

In other words, as at this point the water boils at a lower temperature, it heats less, so that the food takes longer to cook (because it is necessary to increase the cooking time in order to have a well done food).

This is because as the height increases, the atmosphere becomes drier, the air has less oxygen and moisture evaporates quickly, therefore, it is sometimes necessary to add more water to compensate this evaporation during cooking.

Hence, at higher altitudes, the cooking time will be longer.

Operant conditioning, sometimes called instrumental learning, was first extensively studied by Edward L. Thorndike, who observed the behavior of cats trying to escape from home-made puzzle boxes.

Hope this helps!

When light strikes a red object, the light waves of all colors except red are absorbed into the object, and never heard from again. (B)

The only thing left to bounce off of the object into anyone's eye is the waves of red.

When light strikes a red object, the light waves of all colors except red are absorbed. The correct option is B.

The light is the ray form of energy which falls on the object to enlighten them and make us able to see that object.

if an object is red, it will absorb almost all colors except red.  The light falling on red object, couldn't absorb the red color. It is the only color which is completely reflected back.

Thus, when light strikes a red object, the light waves of all colors except red are absorbed. The correct option is B.

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Answer:

they get cool

Explanation:

Billy left some rocks inside for the night. The rocks will be cooled as they stay out all night.

When the temperature of any object increases, it becomes hot. The same way, if the temperature decreases, it gets cold.

The sunlight carries the heat in the form of light rays. As they fall on the rock when kept outside in the Sun, they become hot. After the sunset, the surrounding temperature get down to the lowest. The temperature of the rock will also be decreased.

Thus, the rocks as they stay out all night, will get cold.

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Answer:

144 ft

Explanation:

h(t) = -16t² + 64t + 80

The maximum height is at the vertex.  We can find the vertex of a parabola using -b / (2a):

t = -64 / (2×-16)

t = 2

The vertex is at 2 seconds.  The height of the stone at this time is:

h(2) = -16(2)² + 64(2) + 80

h(2) = 144

The maximum height is 144 feet.

Final answer:

To find the maximum height that the stone reaches, calculate the vertex of the quadratic equation, which leads to a time of 2 seconds. Substituting this back into the height function h(t), we find that the stone reaches its maximum height of 144 feet above the ground.

Explanation:

To determine the maximum height the stone reaches in the given quadratic function h(t) = -16t2 + 64t + 80, we need to find the vertex of the parabola. The vertex form of a parabola is y = a(x - h)2 + k, where (h, k) is the vertex of the parabola. Since our parabola opens downward (a = -16), the vertex will represent the maximum point.

The vertex of the parabola h(t) can be found by using the formula h = -b/2a, where a and b are coefficients from the quadratic equation in the form ax2 + bx + c. In this case, a = -16 and b = 64. Plugging these values into the vertex formula, we get h = -64/(2*-16), which simplifies to h = 2 seconds. This is the time at which the maximum height is reached.

Now, we can find the maximum height by substituting t = 2 back into the original equation to get h(2) = -16(2)2 + 64(2) + 80, which equals 144 feet. Therefore, the maximum height reached by the stone is 144 feet.

Answer:

It is called Perihelion.

Explanation:

Answer:

0.687 m/s

Explanation:

Initial energy = final energy

1/2 mu² = mgh + 1/2 mv²

1/2 u² = gh + 1/2 v²

Given u = 2.00 m/s, g = 9.8 m/s², and h = 0.180 m:

1/2 (2.00 m/s)² = (9.8 m/s²) (0.180 m) + 1/2 v²

v = 0.687 m/s

The final speed of the toy car is about 0.687 m/s

[tex]\texttt{ }[/tex]

Let's recall Kinetic Energy Formula as follows:

[tex]\large {\boxed{Ek = \frac{1}{2}mv^2} }[/tex]

Ek = Kinetic Energy ( Joule )

m = mass of the object ( kg )

v = speed of the object ( m/s )

Let us now tackle the problem !

[tex]\texttt{ }[/tex]

Given:

mass of toy car = m = 100 g

initial speed of toy car = u = 2.00 m/s

initial height position of toy car = h₁ = 0 m

final height position of toy car = h₂ = 0.180 m

Asked:

final speed of toy car = v = ?

Solution:

We will use Conservation of Energy to solve this problem:

[tex]Ep_1 + Ek_1 = Ep_2 + Ek_2[/tex]

[tex]mgh_1 + \frac{1}{2} m u^2 = mgh_2 + \frac{1}{2} m v^2[/tex]

[tex]0 + \frac{1}{2}mu^2 = mgh_2 + \frac{1}{2} m v^2[/tex]

[tex]\frac{1}{2}u^2 = gh_2 + \frac{1}{2}v^2[/tex]

[tex]u^2 = 2gh_2 + v^2[/tex]

[tex]v^2 = u^2 - 2gh_2[/tex]

[tex]v = \sqrt {u^2 - 2gh_2}[/tex]

[tex]v = \sqrt {2.00^2 - 2(9.8)(0.180)}[/tex]

[tex]v \approx 0.687 \texttt{ m/s}[/tex]

[tex]\texttt{ }[/tex]

[tex]\texttt{ }[/tex]

Grade: High School

Subject: Physics

Chapter: Energy

Answer:

0.45

Explanation:

Answer:

B (USA TestPrep)

Explanation:

A heavy nucleus splits into two smaller nuclei is true about fission reaction.

Nuclear fission is the splitting of a heavy nucleus into two lighter ones. Fission was discovered in 1938 by the German scientists Otto Hahn, Lise Meitner, and Fritz Strassmann, who bombarded a sample of uranium with neutrons in an attempt to produce new elements with Z > 92.

Nuclear fusion, in which two light nuclei combine to produce a heavier, more stable nucleus, is the opposite of nuclear fission.

As in the nuclear transmutation reactions discussed.  the positive charge on both nuclei results in a large electrostatic energy barrier to fusion.

Therefore, A heavy nucleus splits into two smaller nuclei is true about fission reaction.

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Answer:

metals,nonmetals, and inert gases

Explanation:

Metals, non-metal and noble gases are the three categories useful for classifying the elements in periodic table.

Explanation:

Elements are defined as a vertical group and a horizontal period in periodic table. Metals, non-metal and noble gases are the three categories useful for classifying the elements in periodic table.

A large number of elements in periodic table flow under the Metals category. Non-metal in the table are mostly gaseous. Noble gases in the table are colorless and non-reactive.

Answer:

-21.6 m/s^2

Explanation:

First of all, we need to convert the initial and final velocities into m/s:

[tex]u = 24,000 km/h = 6666.7 m/s[/tex] is the initial velocity

[tex]v=17,000 km/h =4722.2 m/s[/tex] is the final velocity

The acceleration is given by

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

where

t = 90 s is the time elapsed

Substituting the numbers, we find

[tex]a=\frac{4722.2 m/s-6666.7 m/s}{90 s}=-21.6 m/s^2[/tex]

and the negative sign means the rocket is decelerating.

Given the initial and final velocity, the negative acceleration ( re-tardation ) of the rocket in space is -21.6m/s².

Motion is simply the change in position of an object over time.

From the First Equation of Motion;

v = u + at

Where v is final velocity, u is initial velocity, a is acceleration and t is time elapsed.

Given that;

v = u + at

at = v - u

a = ( v - u )/t

a = ( 4722.22m/s - 6666.67m/s ) / 90s

a = ( -1944.45m/s ) / 90s

a = -21.6m/s²

Given the initial and final velocity, the negative acceleration ( re-tardation ) of the rocket in space is -21.6m/s².

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Answer:

640 J

Explanation:

The work done by the piston when expanding is given by

[tex]W=p\Delta V[/tex]

where we have

[tex]p=200 kPa = 2.0\cdot 10^5 Pa[/tex] is the pressure

[tex]\Delta V[/tex] is the change in volume of the gas inside the piston;

since we have

[tex]V_i = 0.2 L[/tex] is the initial volume

[tex]V_f = 3.4 L[/tex] is the final volume

The change in volume is

[tex]\Delta V=3.4 L-0.2 L=3.2 L=3.2\cdot 10^{-3} m^3[/tex]

and so the work done is

[tex]W=(2.00\cdot 10^5 Pa)(3.2 \cdot 10^{-3}m^3)=640 J[/tex]

Answer:

option d: microwave industrial drying equipment

Explanation:

Answer:

E) 1500 N

Explanation:

The total height from which Santa has fallen down is

h = 9 m + 2 m = 11 m

So its gravitational potential energy at the beginning was

[tex]U=mgh=(120 kg)(9.81 m/s^2)(11 m)=12,949 J[/tex]

While sliding down, Santa has lost all its gravitational potential energy: this energy has been converted into thermal energy due to the presence of the friction. So, the work done by friction is exactly equal to the initial potential energy of Santa:

[tex]W=12,949 J[/tex]

The work done by friction is

[tex]W=Fd[/tex]

where

F is the force of friction

d = 9 m is the length of the chimney (the distance through which the frictional force acts)

Solving the equation for F, we find

[tex]F=\frac{W}{d}=\frac{12,949 J}{9 m}=1439 N[/tex]

So the closest option is

E) 1500 N

Answer:

the volume will increase

Explanation:

if the temperature is held constant , the equation is reduced yo Boyle's  law

Explanation:

The amount of heat [tex]Q[/tex] absorbed in the temperature variation of a material is:

[tex]Q=m. c. \Delta T[/tex]   (1)

Where:

[tex]m=435g[/tex]  is the mass  of water

[tex]c[/tex]  is the specific heat of the element. In the case of water [tex]c=1 cal/g\°C [/tex]

[tex]\Delta T[/tex]  is the variation in temperature, which in this case is  [tex]\Delta T=100\°C-25\°C=75\°C[/tex]  

(The boiling point of water at the pressure of 1 atm is  [tex]100\°C[/tex])

Rewriting equation (1) with the known values:

[tex]Q=(435g)(1 cal/g\°C)(75\°C)[/tex]  

(2)

[tex]Q=32625 cal[/tex]   (3)

Nevertheless, we are asked to find this value in Joules. So, we have to convert this 32625 calories to Joules, knowing the following:

[tex]1 cal=4.187 J[/tex]   (4)

Hence:

[tex]Q=32625 cal=136600.875 J=136.6kJ[/tex]  

The downward force of your weight on the floor and the upward force of the floor against the bottom of your shoes are an action-reaction pair.

Those two forces against the soles of your shoes are equal and opposite forces.  If they were not equal and opposite, then they would add up to something that would not be zero.  There would be some NET force there, and the soles of your shoes would be accelerating up or down.  Since they're NOT doing that, and you're just standing there motionless, there can't be any net force there.  Those two forces must exactly add up to zero.

Answer:

two forces such as weight and normal that are in the same body are not the force of action and reaction

Explanation:

Newton's third law says: "If two bodies interact the force exerted by the body 1 on the body 2 is of equal magnitude and opposite to the force exerted by the object 2 on the 1"

Let's analyze this sentence in our case, the bodies are the Earth and the chair

The Earth pulls the body creating its weight at the same time the body pulls the Earth, with an equal force, notice that each force is applied to a different body, so they cannot be added. These are forces of action and reaction

The chair does not accelerate due to its weight because it is supported by the floor, but it creates a very small deformation that creates a response called Normal force to this support, applied to the chair. The force of the deformation is applied to the floor. These are forces of action and reaction.

Therefore two forces such as weight and normal that are in the same body are not the force of action and reaction

Answer:

A

Explanation:

The horizontal component of the resultant vector is:

x = 18 cos 70° + 15

x = 21.2

The vertical component of the resultant vector is:

y = 18 sin 70°

y = 16.9

So the angle from the positive x-axis is:

θ = atan (y/x)

θ = atan (16.9 / 21.2)

θ = 39°

Answer is A.

The Wright brothers, Wilbur and Orville, were pioneers of aviation, since they flew in a device heavier than air, which was inconceivable at that time.

Their first successful flight was on December 17th, 1903 in Kitty Hawk, North Carolina, which lasted only 12 seconds in which their plane (the Flyer I, with 341 kg, 6.4 m long and a wingspan of 12.3 m) traveled 37 m without touching the ground. This was achieved through the help of an external catapult that "threw" them into the air.

It should be noted that the Wright brothers only studied until high school, however, their passion for solving the problem of the human inability to fly, their perseverance and experience acquired over the years in their bicycle company, led them to reach that goal. An achievement that marked the beginning of the  aviation era.

Answer:

Supernova

Explanation:

A supernova explosion occurs when a high mass star ends its life cycle.

When a very massive star runs out of hydrogen used in the core for the nuclear fusion, it starts burning heavier and heavier elements (helium, carbon, etc.). However, this process stops when the star has burnt all elements lighter than iron: in fact, nuclear fusion of the iron cannot occur, since the process releases less energy than the amount of energy needed to start it. At this point, therefore, the star can no longer produce energy by nuclear fusion, and there is no longer any outward pressure that can counterbalance the gravitational force of the star, pushing inward: as a result, the star collapses under the action of gravity, and the outer layers "bounce off the core" producing a huge explosion called supernova.

The remnant of the supernova explosion is, depending on the mass of the star, a neutron star or a black hole.

Final answer:

Massive stars end their life cycle in a spectacular explosion called a supernova, with type II being associated with massive star collapse and type Ia with white dwarf explosions.

Explanation:

Massive stars terminate in a brilliant explosion known as a supernova. This explosion is one of the most spectacular celestial events and happens when a massive star collapses at the end of its life cycle. There are different types of supernovae, but the one caused by the collapse of a massive star is specifically called a type II supernova. Moreover, when white dwarfs explode due to gathering too much mass, they are termed type Ia supernovae, leaving behind no remnant. The death of very massive stars that do not explode in a supernova can lead to the formation of a black hole, adding another layer of complexity to stellar evolution.

Answer:

The distance between interference fringes increases

Explanation:

Answer:

c) Because light is packaged discretely, increasing the intensity of light will increase the number of photons hitting a metal and thus the likelihood that an electron will be ejected.

Explanation:

In the photoelectric effect, light incident with a certain frequency causes the emission of photoelectrons from the surface of a metal. This effect is explained by considering light a "package" of several quanta, called photons: each photon hits only 1 electron at time, giving all its energy to the electron. If the energy given is above the work function, then the electron has enough energy to leave the metal.

The energy given off by the photon only depends on the frequency of the light, not on the intensity, according to the formula

[tex]E=hf[/tex]

where h is the Planck constant and f the frequency.

In this model, one photon hits only 1 electron at time: this means that the intensity of light (which is a measure of the number of photons in the light) does not affect the probability  of emitting an electron from the material, because that probability depends only on the energy of the photon, which depends only on the frequency of the light.

So, statement c) is wrong.

Final answer:

The correct statement about Einstein's explanation of the photoelectric effect is that the kinetic energy of the ejected electrons is directly related to the frequency of the light.

Explanation:

In Einstein's explanation of the photoelectric effect, statement d) The kinetic energy of electrons leaving the metal does not depend on the intensity of the light because intensity only affects the numbers of light packages, not their energy, is not correct.

The correct statement is that the kinetic energy of the ejected electrons is directly related to the frequency of the light. Higher frequency photons have more energy, and when they strike the metal surface, they can transfer enough energy to the electrons to overcome the work function and eject them.

Additionally, increasing the intensity of the light does not increase the energy of the individual photons, but it does increase the number of photons hitting the metal. This can increase the number of ejected electrons, but the kinetic energy of each individual electron is determined by the frequency of the photons, not the intensity of the light.

Answer: the answer is red which its wavelength is slighty longer than blues

Red light has the longest wavelength among visible colors.

Red light has the longest wavelength among the colors of visible light. The main colors of visible light, from longest to shortest wavelength, can be remembered using the mnemonic ROY G BIV- Red, Orange, Yellow, Green, Blue, Indigo, and Violet. Violet, on the other hand, has the shortest wavelength among the colors of visible light.

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Energy = (power) x (time)

Energy = (4.5 kW) x (5 hours)

Energy = (4.5 x 5) kW-h

Energy = 22.5 kW-h

Answer:

See below.

Explanation:

That would be 4.5 * 5 = 22.5 kilowatt hours.

Answer:

An electric circuit

Explanation:

(a) 18.3 m/s

According to the law of conservation of momentum, the total initial momentum of the system must be equal to the total final momentum, so we have

[tex]p_i = p_f\\m u = (m+M)v[/tex]

where

m = 0.0240 kg is the mass of the bullet

u = 400 m/s is the initial speed of the bullet

M = 0.5 kg is the mass of the block

v is the final speed of the block+bullet together

Solving for v, we find the velocity after the collision

[tex]v=\frac{mu}{m+M}=\frac{(0.0240 kg)(400 m/s)}{0.0240 kg+0.5 kg}=18.3 m/s[/tex]

(b) 17.0 m/s

The frictional force acting on the bullet-block system is

[tex]F_f = -\mu (m+M)g[/tex]

where

[tex]\mu = 0.30[/tex] is the coefficient of kinetic friction

The acceleration due to the frictional force, therefore, will be equal to the frictional force divided by the total mass:

[tex]a=\frac{F_f}{m+M}=\-mu g = -(0.30)(9.8 m/s^2)=-2.94 m/s^2[/tex]

The system travels for a distance of

d = 8.0 m

So we can find the final velocity using the equation:

[tex]v_f^2 = v^2 + 2ad[/tex]

where

v = 18.3 m/s is the initial velocity, found at point a). Substituting,

[tex]v_f = \sqrt{(18.3 m/s)^2+2(-2.94 m/s^2)(8.0 m)}=17.0 m/s[/tex]

(c) 2.1 m

We can use again the law of conservation of momentum:

[tex](m+M) v = (m+M+M')v'[/tex]

where

v = 17.0 m/s is the initial velocity of the initial bullet+block system

M = 2.00 kg is the mass of the second block

v' is the final velocity of the system

Solving for v',

[tex]v=\frac{(m+M)v}{m+M+M'}=\frac{(0.0240 kg+0.5 kg)(17.0 m/s)}{0.0240 kg+0.5 kg+2.00 kg}=3.5 m/s[/tex]

The acceleration of the system on the rough surface is still

[tex]a=-2.94 m/s^2[/tex]

So we can find the distance covered by using again the formula used before, and requiring that the final velocity should be zero (v''=0):

[tex]v''^2 - v'^2 = 2ad\\d=\frac{v''^2-v'^2}{2a}=\frac{0-(3.5 m/s)^2}{2(-2.94 m/s^2)}=2.1 m[/tex]

a)The velocity of the combined bullet and block just after collision is 18.32 m/s. b)After sliding with friction, the velocity is 16.99 m/s, and c) after sticking to a 2.00 kg block, the combined system travels 2.13 m before stopping.

First, we need to find the velocity of the combined bullet and block system just after the collision using conservation of momentum.

(a) Using conservation of momentum:

initial momentum = final momentum

m₁ = mass of bullet , v₁= vel of bullet , m₂ = mass of block ,v₂ = final velocity

( m₁ × v₁) = (m₁ + m₂) × v₂

(0.0240 kg × 400 m/s) = (0.0240 kg + 0.500 kg) × v₂

9.6 kg×m/s = 0.524 kg × v₂

v₂ = 9.6 kg×m/s / 0.524 kg

v₂ ≈ 18.32 m/s

(b) To find the velocity after sliding with friction:

The work done by friction = kinetic energy loss , total mass = M

friction force = μ × M × g

work done by friction = friction force × distance

M = 0.524 kg

μ = 0.30

d = 8.0 m

work = μ × M × g × d

work = 0.30 × 0.524 kg × 9.8 m/s² × 8.0 m

work ≈ 12.31 J

initial kinetic energy = 0.5 × M × (v₂)²

initial kinetic energy ≈ 0.5 × 0.524 kg × (18.32 m/s)² ≈ 87.84 J

final kinetic energy = initial kinetic energy - work by friction

final kinetic energy ≈ 87.84 J - 12.31 J ≈ 75.53 J

final velocity = √(2 × final kinetic energy / M)

final velocity ≈ √(2 × 75.53 J / 0.524 kg) ≈ 16.99 m/s

(c) To find the distance traveled after sticking to the 2.00 kg block:

Using conservation of momentum:

(m₃ × v₂) = (m₃ + m₄) × V   , V = final velocity new

mass of bullet block ≈ m₃ = 0.524 kg

mass of new block = m₄ = 2.00 kg

(m₃ × final velocity found in (b))

0.524 kg × 16.99 m/s = (0.524 kg + 2.00 kg) × V

8.90 kg×m/s = 2.524 kg * V_new_final

V ≈ 3.53 m/s

Now we deal with the kinetic friction again to find the stopping distance:

work = μ × M₁ × g × d  , M₁ = new total mass

M₁ = 2.524 kg

μ = 0.30

work = 0.3 × 2.524 kg × 9.8 m/s² × d

initial kinetic energy = 0.5 × M₁ × V₁²

initial kinetic energy ≈ 0.5 × 2.524 kg × (3.53 m/s)² ≈ 15.70 J

work = initial kinetic energy

0.3 × 2.524 kg × 9.8 m/s² × d = 15.70 J

d ≈ 2.13 m

Answer:

the experyoeyv

Explanation:

EACH of these statements CAN be true or false.  They ALL depend on the situation, and on the components of the particular circuit.  

For each of these statements, I can give you the diagram of a circuit in which the statement is true, and I can give you the diagram of another circuit in which the same statement is false.

These choices are usually true:

-- Changing the frequency does not affect the current.

-- Increasing the resistance decreases the current.

-- Increasing ΔVmax increases the current.  

These choices are usually false:

-- Increasing the frequency increases the current.

-- Changing ΔVmax does not affect the current.

-- Changing the resistance does not affect the current.  

-- Increasing ΔVmax decreases the current.

-- Increasing the resistance increases the current.

-- Increasing the frequency decreases the current.

These choices can go either way just as easily:

-- Voltage leads current.

-- Current and voltage are in phase.

-- Current leads voltage.

Atoms and elements are pure substances.

Elements are pure substances made up of one type of atom. Atoms are the smallest unit of an element and include protons, neutrons and electrons. The number of protons in an atom defines the element it represents.

The relationship between atoms and elements is foundational to the study of chemistry. Elements are pure substances that consist of only one type of atom. For instance, the element gold is made up of only gold atoms, and the element oxygen is made up of only oxygen atoms.

Atoms are the smallest unit of an element that retains the properties of that element. They are composed of protons, neutrons and electrons. The number of protons in an atom determines the element it represents. For example, an atom with one proton is a hydrogen atom, whereas an atom with six protons is a carbon atom.

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Answer: 225.0 m

Explanation:

Because you asked for distance, and not displacement, you simply need to add 150m + 75m, which is 225 m.