PLZ HELP: Which food items would be appropriate for a spacecraft? Check all that apply. A< brownie, B< dry salt and pepper, C

Fracture toughness, minimum crack length calculation for fracture under stress.

Fracture toughness is the ability of a material to resist brittle fracture when a crack is present. In this scenario, we are given a fracture toughness value of 82.4 MPa√m.

To determine the minimum length of a surface crack that will lead to fracture when exposed to a tensile stress of 345 MPa, we can use the plane strain fracture toughness formula.

By plugging in the given values and solving the equation, we can find the minimum length of the surface crack that will cause fracture.

To find the minimum crack length that could lead to fracture in a steel plate, the plane strain fracture toughness equation is used, incorporating the values for fracture toughness, applied stress, and the geometric factor Y.

To determine the minimum length of a surface crack that will lead to fracture in a steel plate subjected to a tensile stress during service, we can use the plane strain fracture toughness equation:

\[a = \left(\frac{1}{\pi} \cdot \left(\frac{K_{IC}}{\sigma \cdot Y}\right)^{2}\right)
\]

Where:

Plugging in the values, the minimum crack length a can be calculated as follows:

\[a = \left(\frac{1}{\pi} \cdot \left(\frac{82.4 \, \text{MPa}\sqrt{m}}{345 \, \text{MPa} \cdot 1.0}\right)^{2}\right)
\]

After calculating the expression inside the parenthetical first and then squaring it, you would divide by π to get the minimum crack length a.

The work done by Sam to stop the coming boat in the amusement park is  [tex]\boxed{845\,{\text{J}}}[/tex].

Further Explanation:

As the boat in the amusement park is moving at a certain velocity, the boat has the kinetic energy stored in it. This kinetic energy of the boat is due to the motion of the boat.

Sam needs to do the work against this energy of the boat to bring it to rest.

The initial kinetic energy of the boat is expressed as:

[tex]\begin{aligned}{K_i}&= \frac{1}{2}m{v^2}\\&=\frac{1}{2} \times 1000 \times {\left( {1.3} \right)^2}\\&= \frac{{1690}}{2}\,{\text{J}}\\&= 8{\text{45}}\,{\text{J}}\\\end{aligned}[/tex]

The boat is brought to rest finally. So, the final kinetic energy of the boat will be  .

The amount of work required to be done by Sam will be equal to the change in kinetic energy of the boat.

[tex]\begin{aligned}W&= {K_f} - {K_i}\\&=0 - 845\\&=- 845\,{\text{J}}\\\end{aligned}[/tex]

Here, the negative work done means that the work is to be done by Sam on the boat in the opposite direction to stop it.

Thus, the work done by Sam to stop the coming boat in the amusement park is  [tex]\boxed{845\,{\text{J}}}[/tex].

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Answer Details:

Grade: College

Subject: Physics

Chapter: Work-Energy Theorem

Keywords:  Sam’s job, amusement park, slow down, boats in the long ride, kinetic energy, work done, boat drift at 1.3m/s, to stop the boat, energy stored in boat.

Sam performs -650 Joules of work to bring the boat to a halt. The negative sign is conventionally used to show that energy has been removed from the system.

To answer your question, we will use the physics concept of work and kinetic energy. Work done on an object is equal to the change in its kinetic energy. In this case, Sam has to stop the boat from its current speed to a rest state. That means the initial kinetic energy of the boat is 0.5*1000 kg*(1.3 m/s)^2 and the final kinetic energy is 0, since it's stopped.

The work Sam does stopping the boat is equal to the change in kinetic energy, which is final kinetic energy - initial kinetic energy. This will result in -650 Joules.

The negative sign indicates that energy has been taken out of the system - in this case by Sam slowing down the boat. It's important to note, however, that in the real world work has to be done against things such as water resistance, but these factors were not included in the question and therefore not considered in the answer.

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Calcium carbonate is one f the most commonly found material found in limestone rocks. The composition of calcium and magnesium as it commonly made of fossils, shells, and debris.

Hence the rocks can be easily be identified by the white to grayish color and presence of lime content in rocks.

learn more about the organic materials that make up limestone.

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Answer:

The answer is C. The glove pushing on the ball. I took a test that had this exact question and it was correct.

A. All matter in the universe was compressed Into a single point.

(apex)

A. All matter in the universe was compressed Into a single point. this option describes the big bang theory.

The Big Bang hypothesis states that all of the current and past matter in the Universe came into existence at the same time, roughly 13.8 billion years ago.

At this time, all matter was compacted into a very small ball with infinite density and intense heat called Singularity.

The universe begin;

The Big Bang was the moment 13.8 billion years ago when the universe began as a tiny, dense, fireball that exploded.

Here Most astronomers use the Big Bang theory to explain how the universe began, But what caused this explosion in the first place is still a mystery.

Thus matter was compressed into a single point and then exploded outward to form the universe describes the big bang theory.

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To determine Morgan's position on the bed (whether standing, sitting, or lying), one must calculate the area of contact she has with the bed using her mass and the pressure she exerts. By comparing the calculated contact area with typical areas for different positions, one can infer her position.

The question asks to determine whether Morgan is standing, sitting, or lying on the bed based on the pressure she exerts on the mattress and her mass of 85 kg. Pressure is defined as the force applied per unit area; in this case, force is due to Morgan's weight. Given that Morgan's weight (W) is the product of her mass (m) and Earth's gravity (g), we can write W = m * g = 85 kg * 9.81 m/s2. The weight finds us the force Morgan exerts downward.

To find the area of contact (A), we rearrange the pressure formula P = F/A, to A = F/P. Inserting the given pressure (P = 9530 N/m2) and her weight calculated earlier, we can find the area. A smaller contact area would suggest standing, while a larger area would suggest sitting or lying down. For example, if calculated area is around the size of feet, she's likely standing; if it's larger - similar to a body's contact area when sitting or much larger - she's sitting or lying down, respectively.

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We solve this using special relativity. Special relativity actually places the relativistic mass to be the rest mass factored by a constant "gamma". The gamma is equal to 1/sqrt (1 - (v/c)^2). 

We want a ratio of 3000000 to 1, or 3 million to 1. 

Therefore:
3E6 = 1/sqrt (1 - (v/c)^2) 
1 - (v/c)^2 = (0.000000333)^2 
0.99999999999999 = (v/c)^2 
0.99999999999999 = v/c 
v= 99.999999999999% of the speed of light ~ speed of light
v = 3 x 10^8 m/s

Final answer:

A fly must travel at speeds approaching the speed of light to have the mass of an SUV according to the theory of relativity. However, such speeds are practically impossible to achieve due to energy limitations and physical laws.

Explanation:

To understand how fast a fly must travel to have the mass of a large SUV, we first need to consider the concept of relativistic mass.

Relativistic mass is an object's mass when it is moving and is given by the equation m = m0 / sqrt(1 - v^2/c^2), where m0 is the rest mass, v is the velocity of the object, and c is the speed of light in a vacuum (approximately 3 x 108 m/s).

Setting the relativistic mass m equal to the mass of an SUV (3000 kg) and solving for v theoretically reveals the speed. However, the answer lies in the realm of speeds very close to the speed of light, indicating an exponential increase in mass as speed approaches c.

This illustrates a principle of Einstein's theory of relativity: as an object's speed approaches the speed of light, its mass approaches infinity, requiring infinite energy to reach c.

Practically, even for an immense acceleration, a fly cannot reach such speeds due to the limitations of energy sources and the law of physics as we understand them. Thus, the question is more theoretical than practical, highlighting the fascinating insights of relativistic physics rather than providing a scenario that could occur in the real world.

The answer is watershed. It is an area of land that drains all the rainfall and streams to a shared passage for instance, mouth of a bay, the outflow of a reservoir, or any point alongside a stream network. The word watershed is occasionally used interchangeably with catchment or drainage basin. This contains surface water like reservoirs, streams, lakes, and wetlands.

Answer:

THe answer is watershed

Explanation:

Final answer:

The density of the unknown substance with a mass of 1.20 g and volume of 1.73 cm³ is found by dividing the mass by the volume, yielding approximately 0.694 g/cm³.

Explanation:

The question involves calculating the density of an unknown substance given its mass and volume. To find the density, the formula Density = Mass/Volume is used. In this case, the mass of the unknown substance is 1.20 grams (g) and its volume is 1.73 cubic centimeters (cm³).

Using the formula:

Density = Mass/Volume
Density = 1.20 g / 1.73 cm³
Density = 0.693641618497 g/cm³

Thus, the density of the unknown is approximately 0.694 g/cm³ (rounded to three decimal places).

Answer:

12 m/s bye

Explanation:

The velocity of the object is 12 m/s. The correct answer is 12 m/s. The correct option is (e).

The kinetic energy (KE) of an object can be calculated using the formula:

KE = 0.5 × m × v²

Where:

KE is the kinetic energy

m is the mass of the object

v is the velocity of the object

The object has a mass of 11 kilograms and kinetic energy of 792 joules, we can rearrange the formula to solve for velocity:

v² = (2 × KE) / m

v = √((2 × KE) / m)

v = √((2 × 792) / 11)

v = 12 m/s

So, the correct answer is 12 m/s. The correct option is (e).

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The maximum acceleration of the truck so that the box remains at rest can be determined using the coefficient of static friction and gravity, which gives us an expression of a_max = µ_s * g. Doubling the mass of the box does not change the maximum acceleration.

The maximum acceleration of the truck such that the box remains at rest can be derived from Newton's Second Law, which shows that the force of friction must balance the force due to acceleration. The force of static friction can be calculated as the coefficient of static friction times the normal force, which for a box on a flatbed truck is equal to the mass of the box times gravity. In equation form, we have F_f = µ_s * m * g, where F_f is the static friction force, µ_s is the coefficient of static friction, m is the mass of the box, and g is the acceleration due to gravity.

To calculate the maximum acceleration of the truck, we can equate the force of static friction to the force due to acceleration (F = m * a), which gives us the equation µ_s * m * g = m * a_max, where a_max is the maximum acceleration. Simplifying the equation gives us a_max = µ_s * g as the maximum acceleration of the truck such that the box remains at rest.

If the mass of the box is doubled, the maximum acceleration of the truck required for the box to remain at rest would remain the same. This is because while the force of friction would double due to the increased mass, the force needed to accelerate the box would also double, keeping the acceleration unchanged.

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Final answer:

To heat and melt 3.0 kg of copper initially at 83°C, we need to calculate the heat required for both steps: heating the copper to its melting point and then melting the copper. Heating the copper requires a certain amount of heat energy, while melting the copper requires another amount of heat energy. By adding these two amounts together, we can find the total energy needed.

Explanation:

To calculate the amount of energy needed to heat and melt 3.0 kg of copper initially at 83°C, we need to consider two steps: heating the copper to its melting point and then melting the copper.

First, we calculate the heat required to heat the copper from 83°C to its melting point (which is approximately 1084°C). We can use the formula Q = m * c * ∆T, where Q is the heat energy, m is the mass, c is the specific heat capacity, and ∆T is the temperature change. In this case, ∆T = (1084 - 83)°C = 1001°C.

Second, we calculate the heat required to melt the copper. We can use the formula Q = m * L, where L is the latent heat of fusion. The latent heat of fusion for copper is approximately 334 kJ/kg. Since we have 3.0 kg of copper, the heat required to melt it is 3.0 kg * 334 kJ/kg = 1002 kJ.

Adding the two amounts of heat energy together, we get a total of 1002 kJ + Q from step one.

The orbital period of a spacecraft at an orbit of 300 kilometers above the Earth's surface is around one hour and a half.

Objects, due to their inherent mass, tend to atract each other due to the laws of gravitation. In short words, objects with a huge ammount of mass atract other objects which are less massive, that is why we are all attracted towards the Earth (which is an incredible massive body).

In general this phenomenon is better seen at the astrological level, like planets attracting their moons or asteroids (this is the case of our problem). Even though, planets attract other bodies which are nearby, this doesn't mean that they will ever come into contact, this is the case for object which orbit those planets.

An orbit is a path which a certain body follows around a more massive object, like the moon orbiting the Earth, or the Earth orbiting around the Sun. These orbits are periodic, meaning they happen continuously over time, over and over again, the same way all times. By this reason, they have a period (which is the duration of such orbit).

At this point, there is a background theory that is necessary to derive the equation we're going to use to compute the orbital period, but it escapes the scope of this problem, so we're just going to use the equation. The equation to compute the orbital period is:

[tex]T= 2 \cdot \pi \cdot \sqrt{\frac{a^3}{\mu}}[/tex]

Where a is the distance between the orbiting object (in this case, the spacecraft) and the center of the orbited object (in this case the Earth), and [tex]\mu[/tex] is a constant dependent on the orbited object, it's called Standard Gravitational Parameter, for the Earth it has a value of [tex]3.986 \cdot 10^{14} \cdot \frac{m^3}{s^2}[/tex].

Since the radius of the Earth is 6371 Km, then a would be 6671 Km. Plugging values on the formula, and making sure to apply the correct units (notice how a is expressed in Km and [tex]\mu[/tex] has units of meter cube), we get that the orbital period is 5422 seconds, which is around one hour and half.

Orbit, gravitation, Earth, attraction laws

White Dwarfs are less luminous than the sun, but with hotter surface temperatures. Therefore, option (B) is correct.

A white dwarf can be described as a stellar core remnant made mostly of electron-degenerate matter. A white dwarf is dense because its mass is comparable to the Sun's and volume is comparable to the Earth's.

A white dwarf has faint luminosity which comes from the emission of residual thermal energy and no fusion occurs in a white dwarf. There are currently eight white dwarfs among the 100 star systems nearest the Sun.

The material in a white dwarf has no fusion reactions, so there is no source of energy. It cannot support itself by the energy generated by fusion but is supported by electron degeneracy pressure.

A carbon-oxygen white dwarf approaches this mass limit by mass transfer from a companion star and may explode as a kind Ia supernova via a process called carbon detonation.

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The approximate size of the smallest object on Earth that astronauts can resolve by eye when they are orbiting 250 km above the Earth is approximately 8.2 mm.

The approximate size of the smallest object on Earth that astronauts can resolve by eye when they are orbiting 250 km above the Earth can be calculated using the formula for the minimum resolvable angle, which is given by:

θ = 1.22 * (λ / D)

where θ is the minimum resolvable angle, λ is the average wavelength of light (500 nm), and D is the diameter of the pupil (5.00 mm).

By rearranging the formula and solving for D, we can find:

D = λ / θ = (500 nm) / (1.22 * (250 km))

After converting the units to meters, we get:

D ≈ 8.2 mm

Therefore, the approximate size of the smallest object on Earth that astronauts can resolve by eye when they are orbiting 250 km above the Earth is approximately 8.2 mm.

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