An athlete participating in cross-country spends the afternoon practicing, and at the end is completely exhausted from all the hard word, even though their average velocity during the practice was 0 m/s. Explain how this situation is possible.

Given data:

Initial velocity,

Angle of projection,

The maximum height achieved by the projectile is given as,

Here, g is the acceleration due to gravity.

Substituting all known values,

Therefore, the maximum height achieved by the projectile is 2.86 m.

a) The planar density expression for FCC (100) is 4/a^2.

    The planar density expression for FCC (111) is 2 / [(sqrt(3) / 2) * a^2].

b)  The planar density for the FCC (100) plane is 24.63 atoms/nm^2.

    The planar density for the FCC (111) plane is  12.32  atoms/nm^2.

a) To derive the planar density expression for the FCC (100) and (111) directions in terms of the atomic radius R, we need to consider the arrangement of atoms in these planes.

FCC (100) Plane:

In the FCC crystal structure, there are 4 atoms per unit cell. The (100) plane cuts through the middle of the unit cell, passing through the centers of the atoms at the corners. Since the atoms at the corners are shared with adjacent unit cells, we only count a fraction of these atoms.

For the (100) plane, we have 2 atoms in the plane, located at the corners of the square, and 1/2 atom at each of the 4 face centers. Thus, the total number of atoms in the plane is 2 + (1/2) * 4 = 4 atoms.

The area of the (100) plane is determined by the square formed by the lattice vectors a and a, which gives an area of a^2.

The planar density (PD) is defined as the number of atoms per unit area, so we divide the total number of atoms (4) by the area (a^2):

PD(100) = 4/a^2

FCC (111) Plane:

In the FCC crystal structure, there are 4 atoms per unit cell. The (111) plane passes through the centers of the atoms at the corners and the center of the face. Similarly to the (100) plane, we need to account for the fraction of shared atoms.

For the (111) plane, we have 1 atom in the plane, located at the corner of the equilateral triangle, and 1/3 atom at each of the 3 face centers. Thus, the total number of atoms in the plane is 1 + (1/3) * 3 = 2 atoms.

The area of the (111) plane is determined by the equilateral triangle formed by the lattice vectors a, a, and a, which gives an area of (sqrt(3) / 2) * a^2.

The planar density (PD) is defined as the number of atoms per unit area, so we divide the total number of atoms (2) by the area ((sqrt(3) / 2) * a^2):

PD(111) = 2 / [(sqrt(3) / 2) * a^2]

b) Now, let's compute the planar density values for the FCC (100) and (111) planes using the atomic radius R = 0.143 nm for Aluminum.

For FCC (100) plane:

PD(100) = 4 / a^2

For Aluminum, the lattice constant a is related to the atomic radius R by the formula:

a = 4R / sqrt(2)

Substituting the given value of R = 0.143 nm:

a = 4 * 0.143 nm / sqrt(2) ≈ 0.404 nm

Therefore, the planar density for the FCC (100) plane is:

PD(100) = 4 / (0.404 nm)^2 ≈ 24.63 atoms/nm^2

For FCC (111) plane:

PD(111) = 2 / [(sqrt(3) / 2) * a^2]

Using the calculated value of a = 0.404 nm:

PD(111) = 2 / [(sqrt(3) / 2) * (0.404 nm)^2] ≈ 12.32 atoms/nm^2

Therefore, the planar density for the FCC (111) plane is approximately 12.32 atoms/nm^2

Thus,

a) The planar density expression for FCC (100) is 4/a^2.

    The planar density expression for FCC (111) is 2 / [(sqrt(3) / 2) * a^2].

b)  The planar density for the FCC (100) plane is 24.63 atoms/nm^2.

    The planar density for the FCC (111) plane is  12.32  atoms/nm^2.

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The weight of the skateboard can be expressed as the gravitational force acting on it, which is given by W = mg, where g is the acceleration due to gravity (9.8 m/s^2).

To find the mass of the skateboard, we can use the principle of conservation of momentum:

Before jumping on the skateboard, the total momentum of the system (student + skateboard) is:

p_i = m_student * v_i = (69 kg) * (1.5 m/s) = 103.5 kg m/s

After jumping on the skateboard, the total momentum becomes:

p_f = (m_student + m_skateboard) * v_f

where v_f is the final velocity of the system. Since momentum is conserved, we can equate the two expressions for momentum:

p_i = p_f

(69 kg) * (1.5 m/s) = (69 kg + m_skateboard) * (1.4 m/s)

Solving for m_skateboard, we get:

m_skateboard = (69 kg * 1.5 m/s - 69 kg * 1.4 m/s) / 1.4 m/s = 11.07 kg

So the mass of the skateboard is approximately 11.07 kg.

When the boy falls off the skateboard, the momentum of the system is conserved again. This time, the initial momentum is:

p_i = (69 kg + 11.07 kg) * 1.4 m/s = 108.9 kg m/s

The final momentum is:

p_f = 69 kg * 1.0 m/s + 11.07 kg * v_fs

where v_fs is the final velocity of the skateboard. Since momentum is conserved, we can equate the two expressions for momentum:

p_i = p_f

(69 kg + 11.07 kg) * 1.4 m/s = 69 kg * 1.0 m/s + 11.07 kg * v_fs

Solving for v_fs, we get:

v_fs = [(69 kg + 11.07 kg) * 1.4 m/s - 69 kg * 1.0 m/s] / 11.07 kg

v_fs = 1.02 m/s

Therefore, the final velocity of the skateboard is approximately 1.02 m/s.

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Answer:

1false

2true

Explanation:

yan po I hope it helps po...pa brainlest na lng po

Answer:

t = 2.55 s

Explanation:

Given that,

Height from which the baseball is thrown, h = 155 m

Initial velocity of the baseball, u = -25 m/s

We need to find the time taken by it to reach the ground. Let the time is t. Using equation of kinematics to find it as follows:

\(v=u+at\\\\t=\dfrac{v-u}{a}\\\\t=\dfrac{0-(-25)}{9.8}\\\\t=2.55\ s\)

So, it will take 2.55 seconds to reach the ground.

True. Neutron stars are some of the densest objects that we can directly observe in the universe. These stars are formed when a massive star undergoes a supernova explosion, and the core of the star collapses under its own gravity, creating a super-dense object that is composed almost entirely of neutrons.

The Neutron stars have a mass similar to that of the sun but are only about 10 miles in diameter, making them incredibly compact. Because of their extreme density, neutron stars have very strong gravitational fields and can cause the space around them to warp and bend. They also emit intense radiation, including X-rays and gamma rays, which can be detected by telescopes. Studying neutron stars can provide insights into the fundamental properties of matter, as well as the processes that occur in the most extreme environments in the universe.

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(a) The rock rises to a height of 49.1 m above the edge of the cliff.

(b) The rock has moved horizontally a distance of 58.3 m when it is at maximum altitude.

(c) The rock hits the ground 5.09 s after it is released.

(d) The range of the rock is 148 m.

(e) At t=2.0 s, the horizontal position of the rock is 46.5 m and the vertical position is 14.1 m. At t=4.0 s, the horizontal position is 93 m and the vertical position is -20 m. At t=6.0 s, the horizontal position is 139.5 m and the vertical position is -54.1 m.

When a rock is thrown off a cliff at an angle of 46∘ above the horizontal, the initial velocity can be divided into horizontal and vertical components. The vertical component determines the rock's height above the edge of the cliff.

Using basic trigonometry, we can find that the vertical component of the initial velocity is given by V_y = V_i * sin(θ), where V_i is the initial speed of the rock and θ is the launch angle. Thus, the rock rises to a height of V_y^2 / (2 * g), where g is the acceleration due to gravity. Plugging in the given values, we find that the rock rises to a height of 49.1 m above the edge of the cliff.

At the maximum altitude, the vertical component of the velocity becomes zero. This occurs when the rock reaches its highest point. At this point, the time taken can be found using the equation t = V_y / g. Substituting the values, we find that the time taken is 2.65 s. The horizontal distance traveled during this time can be calculated using the equation d = V_x * t, where V_x is the horizontal component of the initial velocity. Plugging in the values, we find that the rock has moved horizontally a distance of 58.3 m at maximum altitude.

To determine the time it takes for the rock to hit the ground, we can use the equation h = V_y * t - 0.5 * g * t^2, where h is the initial height of the cliff. Solving for t, we find that the rock hits the ground 5.09 s after it is released.

The range of the rock can be calculated using the equation R = V_x * t, where R is the range. Substituting the values, we find that the range of the rock is 148 m.

To find the horizontal and vertical positions of the rock at different times, we can use the equations x = V_x * t and y = V_y * t - 0.5 * g * t^2. Plugging in the values and the given times, we find that at t=2.0 s, the horizontal position is 46.5 m and the vertical position is 14.1 m. At t=4.0 s, the horizontal position is 93 m and the vertical position is -20 m. At t=6.0 s, the horizontal position is 139.5 m and the vertical position is -54.1 m.

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Answer:

I'm not going to give you the direct answer because you shouldn't cheat but I will give a hint

Explanation:

Physics, chemistry, astronomy, geology and other disciplines concerned with the study of non-living things are examples of physical science.

When the spaceship releases its rocket, the rocket will experience a force equal to the mass of the expelled fuel times the acceleration it produces. Assuming the rocket is pushing off against the spaceship with an exhaust velocity of 15 m/s, the force produced can be calculated using the rocket equation:

F = (dm/dt) * ve

where F is the force produced, dm/dt is the mass flow rate of fuel being expelled, and ve is the exhaust velocity.

Let's assume that the rocket is expelling fuel at a constant rate of 1 kg/s. Then, the force produced by the rocket can be calculated as:

F = 1 kg/s * 15 m/s = 15 N

Since the rocket is pushing off against the spaceship, the spaceship will experience an equal and opposite force of 15 N. Using Newton's second law (F = ma), we can calculate the acceleration of the spaceship as:

a = F/m = 15 N / 1500 kg = 0.01 m/s^2

Therefore, the spaceship will experience a very small acceleration of 0.01 m/s^2 when the rocket is expelled. However, this acceleration is negligible compared to the initial speed of the spaceship (40 m/s), so the overall speed of the spaceship will not change significantly.

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The number of atoms on the moon is 1.33× 10¹⁵ atom.

The atom consists of matter that may be split without releasing electrical charges.

It's also the smallest unit of matter with chemical element features. As a result, the atom is the fundamental unit of science.

In the nucleus proton and the neutron is exists. The condition of the atom to be electrically neutral is that the number of the proton and electron should be the same.

The response is 1.33× 10¹⁵ atom. According to the Jefferson Lab of the US Department of Energy.

This answer is derived from an assessment of the number of atoms present in each of the Earth's constituent elements, such as silicon, iron, magnesium, sulfur, and silicon.

Hence the number of atoms on the moon is 1.33× 10¹⁵ atom.

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The Jovian planets are formed from materials different from the terrestrial planets for the reason that gaseous Jovian planets, formed farther away from the heat of the Sun, are formed from light weight nebulae "dust."

A Jovian planet, also known as a gas giant, is a huge planet that has a primarily gaseous composition. The Jovian planets include Jupiter, Saturn, Uranus, and Neptune. They are primarily made up of hydrogen and helium, and they have enormous atmospheres.Jovian planets are formed farther away from the heat of the Sun, so they are formed from lighter-weight nebulae "dust." Terrestrial planets, on the other hand, are formed nearer to the Sun, so they are formed from heavier-weight nebulae "dust." The density of the materials that make up the Jovian planets is lower than that of the terrestrial planets due to this. This means that the Jovian planets have lower densities and a greater volume than the terrestrial planets.

Hence, the correct option is d. Gaseous Jovian planets, formed farther away from the heat of the Sun, are formed from light weight nebulae "dust."

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Answer:

Initial velocity of the van is 4.95m/s

Explanation:

Acceleration is found using the following formula:
\(a=\frac{v-u}{t}\)

where:

a is acceleration ( in meters per second squared)
v is final velocity ( in meters per second)
u is initial velocity ( in meters per second)
t is time ( in seconds)

We know that:
\(a = 2.15m/s^{2}\)

\(v = 20m/s\)

\(t=7s\)

Therefore, we can find the initial velocity by shifting around some values and making \(u\) the subject within the acceleration formula by multiplying both sides by \(t\):
\(a\) × \(t=v-u\)

Followed by:
\(u = v-at\)

Now we can substitute in the values we have:
\(u = 20-(2.15\) × \(7)\)
\(u = 20 - 15.05\)

\(u=4.95m/s\)

Answer:

the heat is growing the particles bigger

Explanation:

answer:

Answer:

yes

Explanation:

Answer:

5 m/s

Explanation:

hope it helps:) u're welcome

The velocity of the duck must be 15 m/s towards the east which is explained below.

The force on a moving charge with some velocity under a magnetic field is given by:

F = qv×B

here q is the charge on the object

v is the velocity of the object

B is the magnetic field

v×B gives the direction of the force

B is towards the north, and Force is directed upwards, then velocity v should be towards the east.

3×10⁻¹¹ = 4×10⁻⁸× v × 5×10⁻⁵

v = 15 m/s

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The major controversy associated with injury as the result of microwave exposure deals with c. Prolonged low levels of exposure. This has been a topic of debate as it is uncertain whether long-term exposure to low levels of microwaves may have adverse health effects.

The major controversy associated with injury as the result of microwave exposure deals with all of the given options, but specifically, the debate revolves around whether prolonged low levels of exposure to microwaves can cause adverse health effects such as leukemia, high levels of microwave absorption leading to tissue damage, the development of cataracts, and other health problems. While some studies suggest that microwave exposure at high levels can cause harm, the evidence regarding the long-term health effects of low-level microwave exposure is still inconclusive and requires further research.

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The interference patterns produced by the two lasers will have the same fringe separation on the screen, located 4.50 m away from the slits.

The interference patterns produced by the two lasers on the screen will exhibit alternating bright and dark fringes. The main answer is as follows:

The fringe separation (distance between adjacent bright or dark fringes) for an interference pattern is given by the equation:

Fringe separation (Δy) = λL / d

Where:

λ is the wavelength of light,

L is the distance from the slits to the screen,

d is the slit separation.

For laser 1:

λ₁ = d/20

For laser 2:

λ₂ = d/15

Since the fringe separation is the same for both lasers, we can set up the following equation:

(λ₁)L / d = (λ₂)L / d

Simplifying, we get:

(1/20)L = (1/15)L

This implies that the fringe separations for both lasers are equal, regardless of their individual wavelengths.

Therefore, on the screen, 4.50 m distant from the slits, the interference patterns created by the two lasers will have the same fringe spacing.

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To solve this problem, we need to use the kinematic equations of motion to determine the hang time of the Cuban tree frog during a single jump.

What is Velocity?

It is defined as the displacement of an object per unit time in a particular direction.

In other words, velocity is the speed of an object in a given direction. It is a vector quantity because it has both magnitude (the speed) and direction.

First, we need to find the vertical component of the initial velocity vector (v0) using the sine function:

sin(26°) = vy / 4.5 m/s

vy = 4.5 m/s sin(26°) = 1.98 m/s

The vertical component of the velocity vector determines how high the frog will jump.

Next, we can use the following kinematic equation to solve for the hang time (t) of the frog:

Δy = v0yt - 1/2 gt^2

where Δy is the vertical displacement (i.e., how high the frog jumps), v0y is the vertical component of the initial velocity vector, g is the acceleration due to gravity (9.8 m/s^2), and t is the hang time.

Since the frog jumps on level ground, its vertical displacement is zero (i.e., it returns to its original height). Therefore, we can simplify the equation as follows:

0 = v0yt - 1/2 gt^2

t(1/2 g t - v0y) = 0

t = 0 or t = 2v0y / g

We can discard the solution t = 0 because it is not physically meaningful. Therefore, the hang time of the Cuban tree frog during a single jump is:

t = 2v0y / g = 2(1.98 m/s) / 9.8 m/s^2 = 0.40 s

Therefore, the answer is (d) 0.40 s.

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The amount of current passing through the point is 1 A

The amount of current passing through the point can be calculated using the formula below.

⇒ Formula:

⇒ Where:

⇒ Make "i" the subject of the equation.

From the question,

⇒ Given:

⇒ Substitute these values into equation 2

Hence, The amount of current passing through the point is 1 A.

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Answer:

The Coriolis effect describes the pattern of deflection taken by objects not firmly connected to the ground as they travel long distances around Earth. ... The key to the Coriolis effect lies in Earth's rotation. Specifically, Earth rotates faster at the Equator than it does at the poles.

-Google

Explanation:

The Coriolis effect is an apparent force brought on by the rotation of the earth.

The Coriolis force is an apparent force brought on by the rotation of the earth. In the northern hemisphere, the Coriolis force causes winds to be deflected to the right, and in the southern hemisphere, to the left. It is often referred to as "Ferrel's Law."

A revolving frame of reference causes an apparent effect known as the Coriolis Effect. When an item travelling straight ahead is observed from a non-fixed frame of reference, the effect happens. The Earth, which spins at a constant speed, serves as the moving frame of reference. Due to Earth's rotation, an object travelling in a straight line that is seen from Earth appears to lose its direction.

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Answer: An owl cause it is a organism

Explanation:

Blue bird is the organism are most likely to die from competition. Bluebird are replaced by the sparrow in many conditions.

Competition is most commonly characterized as the interaction of people vying for a limited-supply shared resource,

Competition in organism can also be defined as the direct or indirect interaction of organisms that results in a change in fitness when they share the same resource.

Bluebird are replaced by the sparrow in many conditions.

Hence, blue bird is the organism are most likely to die from competition.

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The elongation of the spring is 19.9 cm.

What is Buoyant force?

Buoyant force is the upward force exerted on an object when it is immersed or floating in a fluid. It is a result of the pressure difference between the top and the bottom of the object due to the weight of the fluid it displaces. The magnitude of the buoyant force is equal to the weight of the displaced fluid. This is why objects that are less dense than the fluid they are in will float, while objects that are more dense will sink.

The buoyant force acting on the block of wood is given by:

FB = ρVg

where ρ is the density of the water, V is the volume of the displaced water, and g is the acceleration due to gravity.

The volume of the displaced water is equal to the volume of the block, which is given by:

V = m/ρ

= 4.15 kg / 661 kg/m³

= 0.006273 m³

So, the buoyant force is:

FB = ρVg = 1000 kg/m³ * 0.006273 m³ * 9.8 m/s² = 61.38 N

At equilibrium, the weight of the block is balanced by the spring force and the buoyant force:

mg = ks + FB

where m is the mass of the block, g is the acceleration due to gravity, k is the spring constant, s is the elongation of the spring, and FB is the buoyant force.

Solving for s, we get:

s = (mg - FB) / k

s = (4.15 kg * 9.8 m/s² - 61.38 N) / 166 N/m

s = 0.199 m = 19.9 cm

Therefore, the elongation of the spring is 19.9 cm.

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The deceleration experienced by the 1075 N sky diver as he opened his parachute is 13.39 m/s²

Force = mass × acceleration

We know that deceleration is the acceleration of stopping objects. Thus,

Force (F) = mass (m) × deceleration (a)

Thus, we can obtain the deceleration of the sky diver as follow:

Force = mass (m) × deceleration (a)

1469 = 109.69 × a

Divide both sides by 109.69

a = 1469 / 109.69

a = 13.39 m/s²

Thus, the deceleration is 13.39 m/s²

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To minimize heat leak in an IR detector, the sensor housing is held at a low temperature of 80 °K using a mechanical cooler. The sensor is mounted to a frame that operates at a higher temperature of 300 °K. This temperature difference creates a thermal gradient, which causes heat transfer between the two components.

To minimize heat transfer, four identical thin-walled hollow tubes are used. These tubes are 5 cm long with an outer diameter of 1 cm. The thermal conductance of each tube needs to be low enough to limit the total heat leak to less than 400 mW.

To achieve this, materials with low thermal conductivity can be used for the tubes. Additionally, the tubes can be designed with multiple layers or insulation to further reduce heat transfer. It is important to optimize the thermal design and insulation to meet the required heat leak limit.

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Answer:

i think its resonance but if im wrong its my fault

Explanation:

Answer:D.Compound

Explanation: internet