When a wave strikes a solid barrier it behaves like a basketball hitting a backboard this wave behavior years called?
Which statements are correct? Check all that apply. A. An insulator slows the flow of heat. B. A conductor increases the flow of heat. C. A conductor decreases the flow of heat. D. An insulator speeds up the flow of heat.
Which statements are correct? Check all that apply.
A compass is used to make circles and arcs in geometric constructions.
A rough sketch by hand is considered a geometric construction.
Geometric constructions are created with a compass and straightedge.
Protractors are used in geometric constructions to measure degree measures.
Rulers are used in geometric constructions to measure segment lengths.
the answer is 1&3
What is the kinetic energy of the emitted electrons when cesium is exposed to uv rays of frequency 1.9×1015hz? express your answer in joules to three significant figures?
Final answer:
The kinetic energy of the emitted electrons when cesium is exposed to UV rays of frequency 1.9 × 10¹⁵ Hz is approximately 9.51 × 10⁻¹⁹ J.
Explanation:
To find the kinetic energy of the emitted electrons, we need to use the equation:
Kinetic Energy (KE) = Energy of the photon - Work Function
The energy of a photon can be calculated using the equation:
Energy (E) = Planck's constant (h) × frequency (f)
Given that the frequency of the UV rays is 1.9 × 1015 Hz, we can calculate the energy of the photon. The value of Planck's constant is 6.626 × 10-34 J·s.
Let's calculate the energy:
E = (6.626 × 10-34 J·s) × (1.9 × 1015 Hz) = 1.2594 × 10-18 J
Now we need to find the work function of cesium, which represents the minimum energy required to remove an electron from the metal. The work function of cesium is approximately 1.93 eV.
Converting the work function to joules:
1 eV = 1.602 × 10-19 J
1.93 eV = 1.93 × (1.602 × 10-19) J = 3.08786 × 10-19 J
Now we can calculate the kinetic energy:
KE = (1.2594 × 10⁻¹⁸ J) - (3.08786 × 10⁻¹⁹J) = 9.50712 × 10⁻¹ J
Therefore, the kinetic energy of the emitted electrons when cesium is exposed to UV rays of frequency 1.9 × 10¹⁵ Hz is approximately 9.51 × 10⁻¹⁹ J.
According to the law of conservation of energy, energy cannot be _____.
A. changed or destroyed
B. created and destroyed
C. created or destroyed
D. created and changed
Answer: B ; created and destroyed
Explanation:
According to the law of conservation of energy, energy can neither be created nor destroyed but can be converted from one form to another
Which simply means you can't create energy and at the same time you can't destroy it.
An energy can be converted from one form to another that is from potential energy to kinetic energy
There is no destruction of energy in such a process
The Law of Conservation of Energy states that energy cannot be created or destroyed. This means that the total amount of energy in a system remains constant. When energy appears to disappear, it has typically been converted to another form.
Explanation:According to the Law of Conservation of Energy, energy cannot be created or destroyed. This is a fundamental law in physics that states that the total amount of energy in an isolated system remains constant over time. For example, when a ball drops from a height, its potential energy is transformed into kinetic energy as it falls, but the total energy within the system (the ball and the Earth) doesn't change. Therefore, the correct answer is C: created or destroyed.
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Which of the following always increases as a system becomes less organized? A. Entropy B. Heat C. Energy D. Temperature
Entropy, the measure of randomness or disorder in a system, increases when a system becomes less organized, such as when ice melts into water.
When a system becomes less organized, the measure of randomness or disorder that increases is known as entropy.
Entropy is a concept in thermodynamics representing the degree of disorder within a system. As energy disperses and becomes more random, entropy increases. This increase in entropy follows the second law of thermodynamics, which states that entropy of any isolated system not in equilibrium almost always increases; it can be thought of as a natural tendency for systems to move towards disorder and spread out energy. For instance, when ice melts into water, entropy increases because the ordered solid structure gives way to a more disordered liquid state, which requires energy input to maintain.
Select all that apply. Greenhouse gases _____. absorb solar energy absorb carbon dioxide release carbon dioxide are released during the combustion of fossil fuels
Gases that trap heat in atmosphere are called Greenhouse gases (GHGs). Examples are carbon dioxide, water vapour, nitrous oxides etc.
The selected choices are that Greenhouse gases-
1. absorb solar energy
2. are released during combustion of fossil fuels.
. The penalties for a person's second DUI conviction include completion of __________ hours of DUI school.
Which of the following is not a name of a scale for measuring temperature? A. Kelvin B. Celsius C. Absolute D. Fahrenheit
Answer:
Kelvin, Celsius, and Fahrenheit
Explanation:
Identify the following as a suspension or a colloid. sand in water
If an atom has 8 valence electrons, how many electrons does it need to gain to achieve a stable electron configuration?
The Clean Air Act of 1963 was an improvement over the Air Pollution Control Act of 1955 because it _____.
A ramp is 1.0 m high and 3.0 m long. What is the IMA of the ramp?
Final answer:
The Ideal Mechanical Advantage (IMA) of a ramp that is 1.0 m high and 3.0 m long is 3, indicating that the ramp multiplies the input force by a factor of 3.
Explanation:
The IMA (Ideal Mechanical Advantage) of a ramp is determined by the ratio of the distance along the ramp's slope (the length of the incline) to the vertical height of the ramp. To calculate the IMA of this particular ramp, which is 1.0 m high and 3.0 m long, you would divide the length by the height:
IMA = Length of the incline / Height = 3.0 m / 1.0 m = 3.
The Ideal Mechanical Advantage of the ramp is 3. This indicates that the ramp multiplies the input force by a factor of 3, meaning for every 1 unit of force applied along the ramp, the output force that lifts the object is 3 units.
How do you know that forces are balanced when static friction acts on an object?
Static friction ensures forces are balanced when an object is at rest by matching the applied force up to its limit. This balance means that the net external force on the object is zero. Such conditions imply static equilibrium.
When an object is at rest and static friction is acting on it, the forces are said to be balanced. This state of balance or equilibrium exists because the net external force on the object is zero. According to Newton's first law, an object will remain at rest if no unbalanced force acts on it.
To break it down step-by-step:
The object remains at rest, indicating that all forces acting on it are balanced.The static friction force adjusts to exactly match the applied force, up to its maximum limit, preventing motion.This balance implies that the sum of all forces in any direction is zero.For example, consider a heavy crate on the ground. When you apply a small force to push it, if the crate does not move, the force of static friction equals the applied force but in the opposite direction. This indicates static equilibrium where forces are balanced.
To further understand, let's note that static friction does no work because the point of contact does not move relative to the surface. This characteristic helps in identifying balance as no work is done when forces are perfectly equal and opposite.
The energy emitted from the sun is a product of ________.
A 10-kilogram bicycle is traveling at a speed of 2m/s. what is the bike's kinetice energy?
what is the net electrical charge on a magnesium ion that is formed when a neutral atom loses two electrons?
Read the scenario below and answer the question that follows.
Molly and Mark are new parents. Their daughter Alvina often cries when she is uncomfortable. Each time Alvina cries, her parents give her a stuffed rabbit. Eventually, Alvina looks at the rabbit and cries because she associates the rabbit with being uncomfortable.
What is the conditioned stimulus (CS) in this scenario? A. the rabbit B. Alvina being uncomfortable C. Alvina’s parents D. Alvina getting hungry
Answer:
A.
Explanation:
just took it on e2020
Why is a small crescent of light often observed on the moon when it is exactly in the new phase?
the two main currents that affect the united states on the eat coast and west coast
Answer: The California Current and the Gulf Stream.
Explanation:The Gulf Stream is on the East coast it runs southward to northward While The California Current which is also a part of the North Pacific Gyre moves southward along the westward coast if America and ends off at the southward Baja California peninsula.
The California Current is a Pacific Ocean current.
Other Currents in America are Humboldt Current, the Canary Current, the Benguela Current, and the Somali Current.
Discuss how metallic bonding accounts for the common properties of metals
Particles in metals are strongly held by the intermolecular force called metallic bonds. This strong bonding make the metals hard, feasible to conduct thermally and electrically.
What are metals?Metals are electropositive elements in periodic table. The alkali metals, alkaline earth metals and transition metals compose the metallic elements. They all shows the metallic properties such as conductivity, malleability, ductility, luster etc.
Metal are consists of a sea of mobile electrons amidst the pool of positive ions. The metallic particles form a well ordered crystal lattice structure with metal ions connected by strong metallic bonds. The electrons can delocalize into the interstices and make the metal lattice conductive.
The close packed structure of metallic particles with free electrons make metals highly conductive both thermally and electrically. Moreover they exhibit color by the transition of electrons with absorption energy.
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Please I need help with this I'll give medal.
Car A has a mass of 1,200 kg and is traveling at a rate of 22 km/hr. It collides with car B. Car B has a mass of 1,900 kg and is traveling in the same direction at 25 km/hr. Which of the following statements is true?
The momentum before the collision is equal to the momentum after the collision.
The momentum before the collision is greater than the momentum after the collision.
The momentum before the collision is less than the momentum after the collision.,
Which of the following occurs in January when the earth is closest to the sun?
Final answer:
The correct option is A Perihelion. Perihelion is the event that occurs in January when the Earth is closest to the Sun, and it results in the Earth being approximately 91.5 million miles from the Sun.
Explanation:
The event that occurs in January when the Earth is closest to the Sun is called perihelion. This is the point in Earth's elliptical orbit where it is at the minimum possible distance from the Sun. The Earth reaches perihelion approximately around January 3rd, depending on the year, with a slight variation over time.
At perihelion, the Earth is about 91.5 million miles from the Sun, as opposed to during aphelion, the farthest point, when it is about 94 million miles away. During this time, despite the Earth receiving more heat from the Sun, the Northern Hemisphere experiences winter because of the axial tilt directing this hemisphere away from the Sun.
Over long periods, the dates of perihelion and aphelion gradually shift due to the precession of the Earth's orbit. This change can have significant climatic effects over geological timescales.
What is the magnetic force on a proton that is moving at 2.5 107 m/s to the left through a magnetic field that is 3.4 T and pointing toward you? The charge on a proton is 1.6 10-19 C. Use F = qv B sin(). **I know it's between C or D**
A. 4.0 10-12 N left
B. 4.0 10-12 N right
C. 1.4 10-11 N up
D. 1.4 10-11 N down,
Answer: C. 1.4 10-11 N up
Explanation:
The magnetic force, F on a charge q moving with velocity v in a magnetic field B at an angle θ is given by:
F = q v B sin θ
Charge of proton, q = 1.6 × 10⁻¹⁹ C
Strength of magnetic field, B = 3.4 T pointing outwards
velocity of the proton, v = 2.5 × 10⁷ m/s towards left
Magnetic force is given by:
F = 1.6 × 10⁻¹⁹ C× 2.5 × 10⁷ m/s ×3.4 T× sin 90 = 13.6 × 10⁻¹² N = 1.4 × 10⁻¹¹ N up
The direction of the force is given by Lorentz Right hand rule. The fingers point magnetic field, the thumb points towards velocity, then the force on the proton is given by the direction perpendicular to the palm.
The magnetic field acts outwards with velocity of the proton towards left. The force would act perpendicular to the two -upwards.
The magnetic force on the proton is 1.4 \( \times \) 10-11 N upward, calculated using the formula F = qvB and the right-hand rule for the direction.
Explanation:The magnetic force on a proton moving through a magnetic field can be calculated using the formula F = qvB sin(\theta), where F is the force on the particle, q is the charge of the particle, v is the velocity of the particle, B is the magnetic field, and \theta is the angle between the velocity vector and the magnetic field vector.
Given:
Velocity of the proton, v = 2.5 \( \times \) 107 m/sMagnetic field strength, B = 3.4 TCharge of the proton, q = 1.6 \( \times \) 10-19 CAngle between velocity and magnetic field, \theta = 90 degrees (since the magnetic field is pointing toward you and the proton is moving to the left)For \theta = 90 degrees, sin(\theta) = 1, thus,
F = qvB sin(\theta) = qvB
F = (1.6 \( \times \) 10-19 C) \( \times \) (2.5 \( \times \) 107 m/s) \( \times \) (3.4 T)
F = 1.36 \( \times \) 10-11 N
Using the right-hand rule to determine the direction, the thumb points in the direction of the force. In this case, the force will be directed upward if the magnetic field is into the page and velocity to the left.
Therefore, the correct answer is C. 1.4 \( \times \) 10-11 N up.
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What electron current is driven through a 2.3-mm-diameter iron wire by a 0.063 v/m electric field?
To calculate the electron current driven through the iron wire, we need to find the drift velocity and the number of free electrons per cubic meter. By using the formula I = nqAvd, we can calculate the current.
Explanation:The electron current driven through the iron wire can be calculated using the formula I = nqAvd. Given that the electric field is 0.063 V/m, we need to calculate two quantities: the drift velocity (vd) and the number of free electrons per cubic meter(n). We can then substitute these values into the equation to find the current (I).
To calculate the drift velocity (vd), we need to calculate the number of free electrons per cubic meter (n). We can use the density of iron (8.80 × 10³ kg/m³) and the atomic mass of iron (63.54 g/mol) along with Avogadro's number (6.02 × 10²³ atoms/mol) to determine n.
Finally, substituting the values of n, q, A, and vd into the equation I = nqAvd, we can calculate the electron current driven through the iron wire.
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if an elephant has a mass of 2,000 kg, what is its weight on Earth? (1 point) A. 0.0049 N B. 204 N C. 19,600 N D. 43,100 N
Answer:
Option C is correct, 19,600N
Explanation:
An elephant has a mass of 2000kg, m=2000kgGravitational acceleration, g=9.8weight ?thus applying formula; W=mgputting values, W=2000×9.8=19600NWhat is gravitational acceleration?Gravitational acceleration (symbolized g) is a physics term that denotes the strength of a gravitational field. It's measured in meters per second squared ([tex]m/s^{2}[/tex]). 1 g is approximately 9.8 [tex]m/s^{2}[/tex] at the earth's surface.
hence, Option C is correct, 19,600N
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hi please help with this question! Need the workings.
A copper penny has a mass of 2.6 g Assuming it is pure copper, how much of this mass is contributed by a) the neutrons in the copper nuclei b) the electrons.
The answers are
a) 1.41 g
b) 6.5 x 10^-4,
You hear the engine roaring on a race car at the starting line. Predict the changes in the sound as the race starts and the car approaches the camera. A) The sound of the engine will get louder and the pitch lower. Eliminate B) The sound of the engine will get louder and the pitch higher. C) The sound is determined by the car and it will not change in any way. D) The sound of the engine will get louder but the pitch will not change.
B. The sound of the engine will get louder and the pitch higher.
Answer: The correct option is B.
Explanation:
Doppler effect is the phenomenon in which there is an apparent change in the frequency when there is relative motion between source and listener.
When the source and the listener are approaching each other then the frequency increases. The loudness depends on the amplitude. The energy of the wave is directly proportional to the square of the amplitude.
In the given problem, the engine is roaring on a race car at the starting line. There is change in the sound as the race starts and the car approaches the camera.
Pitch depends on the frequency.
Therefore, the sound of the wave will get louder and the pitch will get higher.
When the moon is directly opposite the sun in the sky, its phase is?
Match the type of boundary with its characteristic
The required relation is given in the figure below
ExplanationThere are three main types of plate boundaries:
Convergent boundaries: where two plates are colliding.Divergent boundaries – where two plates are moving apart. ... Transform boundaries – where plates slide passed each otherA dog travels north for 18 meters, east for 8 meters, South for 27 meters and then west for 8 meters. What is the distance the dog traveled and what is the displacement of the dog.
Answer:
Distance = 18 +8+ 27+8 =61
Displacement 27 - 18 = 9
Explanation: