Which is not an example of a lever? light switch scissors knife broom

It's easy to fall into the temptation to say that when the velocity is zero, then the acceleration is also zero. But wait! To answer this question we need to bring out the concept of instantaneous velocity. This type of velocity stands for a specific moment, a specific instant of time, that is, [tex]t=1, \ t=2, \ t=3, \ t=3.2 \ t=4.5[/tex]. If so, then acceleration may not be zero when velocity is zero. For example, suppose you throw an object upward, when it is at the top of the travel the instantaneous velocity is zero because it changes from positive to negative value and there is a moment when it must be zero, but yet there is a constant acceleration by the Earth's gravity at that moment. Even though the velocity at that stationary moment is zero, it doesn't imply the acceleration must be zero, so it has a value and in this case is [tex]-9.8m/s^{2}[/tex]

Answer:

The solubility of most solids decrease as temperatures decreases.

Hope this helps :)

Have a great day !

5INGH

Explanation:

Specular reflection is a mirror-like reflection where light reflects at specific angles, occurring on smooth surfaces and obeying the law of reflection. Diffuse reflection is when light scatters in many directions after hitting a rough surface, allowing us to see objects from different angles. Both types of reflection are explained by the same fundamental law of reflection.

Diffuse vs. Specular Reflection

When light reflects off a surface, the nature of the reflection is determined by the surface's texture. Specular reflection occurs when light strikes a smooth surface, like a mirror, causing light rays to reflect at specific angles maintaining the image's appearance. This type of reflection follows the law of reflection, where the angle of incidence is equal to the angle of reflection. Conversely, diffuse reflection happens when light hits a rough surface, such as paper or clothing. Here, the variance in surface angles causes light to scatter in multiple directions, which enables us to see the object from various perspectives without a distinct reflection of the light source.

Figures referenced in the provided text illustrate these concepts by comparing the predictable reflection from a mirror (specular) with the scattered light from a rough surface (diffuse). This scattering effect of diffuse reflection is what allows us to view nonluminous objects from any angle. It's important to understand that both types of reflections are governed by the law of reflection; it's the surface texture that dictates whether the light is reflected in a singular direction or scattered.

The puck starts with velocity vector

[tex]\vec v_0=\left(2.35\dfrac{\rm m}{\rm s}\right)(\cos(-22^\circ)\,\vec\imath+\sin(-22^\circ)\,\vec\jmath)=(2.18\,\vec\imath-0.880\,\vec\jmath)\dfrac{\rm m}{\rm s}[/tex]

Its velocity at time [tex]t[/tex] is

[tex]\vec v=\vec v_0+\vec at[/tex]

Over the 0.215 s interval, the velocity changes to

[tex]\vec v=\left(6.42\dfrac{\rm m}{\rm s}\right)(\cos50.0^\circ\,\vec\imath+\sin50.0^\circ\,\vec\jmath)=(4.13\,\vec\imath+4.92\,\vec\jmath)\dfrac{\rm m}{\rm s}[/tex]

Then the acceleration must have been

[tex]\vec v=\vec v_0+(0.215\,\mathrm s)\vec a\implies\vec a=\dfrac{\vec v-\vec v_0}{0.215\,\rm s}=(9.06\,\vec\imath+27.0\,\vec\jmath)\dfrac{\rm m}{\mathrm s^2}[/tex]

which has a direction of about [tex]71.4^\circ[/tex].

The direction of the acceleration is determined by the direction of the change in velocity. This would be calculated by subtracting the initial velocity vector from the final velocity vector. However, the calculation would involve complex trigonometric functions.

In order to find the direction of the acceleration, we need to calculate the direction of the change in velocity and that direction will be the direction of the acceleration.

To calculate the change in velocity, we subtract the initial velocity from the final velocity: (6.42 m/s, 50.0°) - (2.35 m/s, -22°). We then calculate the angle of this vector which represents the change in velocity, and hence the direction of acceleration.

However, this calculation is not straightforward because it involves vector operations and would require the use of trigonometric functions to solve. This is due to the fact that velocity is a vector, meaning it has both a magnitude and a direction. Consequently, this becomes a multi-step process involving trigonometry and physics.

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Answer:

Electromagnetic waves

Explanation:

Electromagnetic waves are waves that consist of oscillating electric and magnetic fields, that oscillate perpendicularly to each other and perpendicularly to the direction of propagation of the wave (for such a reason, these waves are also called transverse waves).

Electromagnetic waves always travel in a vacuum at the same speed, called speed of light:

[tex]c=3.0\cdot 10^8 m/s[/tex]

and they are classified into 7 different types, according to their frequency. From lowest to highest frequency, we have:

Radio waves

Microwaves

Infrared

Visible light

Ultraviolet

X-rays

Gamma rays

Therefore, gamma rays, x-rays, visible light and radio waves are all types of electromagnetic waves with different frequencies.

120.0v drop across the 20.0 resistor

Answer:

120.0v drop across the 20.0 resistor

Explanation:

the time it begins to drop

Gravity is a force that acts on the ball throughout its entire journey. However, the point at which gravity is the greatest force acting on the ball is at the highest point of its trajectory.

This is the point where the ball momentarily stops before changing direction and starts to fall back down.

When the ball reaches its highest point, its vertical velocity becomes zero, and for an instant, it is motionless before it starts to fall due to the force of gravity. At this point, gravity is the only force acting on the ball, and it is pulling it downward with the maximum force, trying to bring it back to the ground.

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Answer:

A. Power = Work / Time

Explanation:

Power is the amount of work done over time, or rather the rate of work, which is given by the unit of watts (W). Since work is defined by Force * Displacement, we can also say Power = Force * Displacement / Time.

Answer:

A. P=W÷t

Explanation:

Answer:

The first flowering plants appeared in the Mesozoic era, not the Paleozoic era.

Explanation:

The Mesozoic era was an era where numerous organisms started to develop in very unique and more advanced ways, both the animals and the plants. In the last period of the Mesozoic, the Cretaceous, the first flowering plants started to appear on the scene. This was revolutionary trait of the plants, and soon these plants started to occupy more and more space and became one of the dominant organisms on the planet. Other important evolution that took place in this period are the appearance of the dinosaurs and the mammals, both becoming the dominant animals on the planet, first the dinosaurs, after that the mammals.

Answer:

Use the drop-down menus to match each description to the geologic era it describes.

The first birds and flowering plants appeared during this era. This is also when the most well-known dinosaurs lived.

✔ Mesozoic

Mammals, including humans, emerged during this era.

✔ Cenozoic

At the beginning of this era, animals lived only in water. By the end, some early dinosaurs emerged.

✔ Paleozoic

Explanation

In order to be able to calculate an answer, we must assume that the boat, with her on it, was motionless in the water until she jumped off of it.

I'll make that assumption, and then I'll go ahead and answer the question that I just invented:

-- Before she jumped off of the boat, she had no momentum and the boat had no momentum.  

-- The SUM of (her momentum) + (the boat's momentum) was zero.

-- Momentum is conserved, so the SUM of (her momentum) + (the boat's momentum) has to still be zero after she jumps off of the boat.

-- Momentum = (mass) · (speed in some direction)

The boat's momentum after the jump = (42kg) · (1.5 m/s) that way ==>

The boat's momentum after the jump = 63 kg-m/s that way ==>

Her momentum after the jump has to be 63 kg-m/s this way <==

Her momentum = 63 kg-m/s = (59 kg) · (her speed this way <== )

Divide each side by (59 kg):

Her speed this way <== = (63 kg-m/s <==) / (59 kg)

Her speed = (63/59) · (m/s this way <== )

Her speed = 1.07 m/s opposite to the direction the boat is moving.

= = = = = = = = = =

A casual but striking observation:

Our 'student' is carrying 17 kg more mass than the boat she sails !  

The mind boggles at the implied zaftigkeit.  

To find the speed of the physics student, we can use the principle of conservation of momentum. By setting up an equation using the initial and final velocities of both the student and the sailboat, we can solve for the final velocity of the student. The answer is approximately 0.038 m/s.

To solve this problem, we can use the principle of conservation of momentum. The initial momentum of the system, which includes the student and the laser sailboat, is equal to the final momentum of the system. The momentum of an object is calculated by multiplying its mass by its velocity. We know the mass and velocity of the laser sailboat after the student jumps off, so we can use that information to find the speed of the physics student.

We can set up the equation as follows:

(mass of student)(initial velocity of student) + (mass of sailboat)(initial velocity of sailboat) = (mass of student)(final velocity of student) + (mass of sailboat)(final velocity of sailboat)

Plugging in the given values, we have:

(59 kg)(0 m/s) + (42 kg)(0 m/s) = (59 kg)(final velocity of student) + (42 kg)(1.5 m/s)

Simplifying the equation, we find that the final velocity of the student is approximately 0.038 m/s.

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this is due to the existence of other forces called the strong nuclear forces that overcomes the repulsion forces between the protons and keeps the nucleons holding to each other also there is a type of energy that is called the nuclear binding energy and this energy also works on binding the components of the nucleus together

The atomic nucleus remains stable despite the repulsion between protons due to the strong nuclear force which is much stronger than the electromagnetic force and acts within a very short range in the nucleus. Further stability is ensured by the conversion of the mass defect into binding energy, and programming of specific numbers of protons and neutrons.

The stability of an atomic nucleus despite the repulsion between positively charged protons is due to a force called the strong nuclear force. This force is significantly stronger than the electromagnetic force causing the repulsion, approximately 100 times stronger, and acts between nucleons (protons and neutrons) within a very short range in the nucleus. That's why protons do not just fly apart as we might expect due to their positive charges. Furthermore, a phenomenon called mass defect, according to Einstein's mass-energy equivalence equation, E = mc², also plays into the nuclear stability. The mass of a nucleus is less than the total mass of its individual protons and neutrons, the 'missing' mass has been converted into the binding energy that holds the nucleus together.

However, not all combinations of protons and neutrons result in a stable nucleus. There are patterns to the stability: nuclei with even numbers of protons or neutrons, or those with 'magic numbers' of nucleons, are especially likely to be stable. Also, it is observed that for higher masses, stable nuclei tend to have more neutrons than protons to reduce the Columb repulsion between protons.

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The light turns on immediately due to loosely bound electrons in the conductors that quickly propagate the electrical signal nearly at the speed of light, causing an instantaneous chain reaction and creating a current. The correct option is: C. loosely bound electrons are already present in the wire conductors that make up the circuit.

A light goes on immediately when you flip a switch because loosely bound electrons are already present in the wire conductors that make up the circuit. These electrons move through the circuit quickly, initiating a nearly instantaneous chain reaction that allows the current to flow and the light to turn on almost immediately.

This movement is much quicker than the drift velocity of the electrons, which is the average speed at which they move through the conductor. Instead, the signal that causes the electrons to start moving travels at a fraction of the speed of light, which is why we perceive the light turning on without noticeable delay.

First surface runoff then ground water...

Answer:

The answer is 2,388.56

Explanation:

A pilot flies in a straight path for 1 hour and 30 min. she then makes a course correction, heading 10 degrees to the right of her original course, and flies 2 hours in the new direction. if she maintains a constant speed of 685 miles per hour. and she will be 1486.65 miles far from the starting position.

To find the distance from the starting position of the pilot after the course correction:

The pilot is approximately 1486.65 miles from her starting position.

Answer:

Some work input is lost to friction

Explanation:

The efficiency of a machine is defined as:

[tex]\eta = \frac{W_{out}}{W_{in}}[/tex] (1)

where

[tex]W_{out}[/tex] is the work output

[tex]W_{in}[/tex] is the work input

Due to the law of conservation of energy, the work output can never be larger than the work input (because energy cannot be created). Moreover, in real machines part of the work input is lost due to the presence of frictions: as a result, part of the energy in input is converted into thermal energy or other forms of energy, and so the work output is smaller than the work input, and so the ratio (1) becomes less than 1, and so the efficiency is less than 100%.

Answer:

Some work input is lost to friction

The machine shown in the diagram is generator.

To produce electricity, a generator needs the input in the form of mechanical energy.

The mechanical energy is the sum of kinetic energy and the potential energy of an object at any instant of time.

M.E = KE +PE

In order to produce electricity, a generator uses the mechanical energy as the input. It gives the electrical energy as output to light up homes, hotels or industries.

Thus, generator is shown in diagram.

Learn more about mechanical energy.

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(a) 4A

In a simple harmonic motion:

- The amplitude (A) is the maximum displacement of the system, measured with respect to the equilibrium position

- The period (T) is the time needed for one complete oscillation, so for instance is the time the system needs to go from position x=+A back to x=+A again

Therefore, we have that in one time period (1T) the distance covered is 4A. In fact, during one period (1T), the system:

- Goes from x=+A to x=0 (equilibrium position) --> distance covered: A

- Goes from x=0 to x=-A --> distance covered: A

- Goes from x=-A to x=0 (equilibrium position) --> distance covered: A

- Goes from x=0 to x=+A --> distance covered: A

So, in total, 4A.

(b) 20A

Since the system moves through a distance of 4A in a time interval of 1T, we can set a proportion to see what is the distance covered in the time 5.00 T:

[tex]1 T : 4 A = 5T : d[/tex]

Solving for d, we find

[tex]d=\frac{(4A)(5T)}{1 T}=20A[/tex]

So, the distance covered in the time 5.00 T is 20 A.

(c) 0.5 T

Since the system moves through a distance of 4A in a time interval of 1T, we can set a proportion to see the time t that the system needs to move through a total distance of 2A:

[tex]1 T : 4 A = t : 2A[/tex]

Solving for t, we find

[tex]t=\frac{(2A)(1T)}{4 A}=0.5 T[/tex]

So, the time needed for the system to move through a total distance of 2A is 0.5T (half period).

(d) 7/4 T

As before, since the system moves through a distance of 4A in a time interval of 1T, we can set a proportion to see the time t that the system needs to move through a total distance of 7A:

[tex]1 T : 4 A = t : 7A[/tex]

Solving for t, we find

[tex]t=\frac{(7A)(1T)}{4 A}=\frac{7}{4}T[/tex]

So, the time needed for the system to move through a total distance of 2A is 7/4 T

(e) 8/5 D

In a time of [tex]\frac{5}{2}T[/tex], the distance covered is 16D.

We also now that the distance covered in 1T is 4A.

So we can find the distance covered in a time of [tex]\frac{5}{2}T[/tex] in terms of A:

[tex]1T:4A = \frac{5}{2}T:d\\d=\frac{(4A)(\frac{5}{2}T)}{1T}=10A[/tex]

And we know that this distance must correspond to 16D, so we can find a relationship between A and D:

[tex]10A=16D\\A=\frac{16}{10}D=\frac{8}{5}D[/tex]

Dark matter is a type of matter, whose composition is unknown and which corresponds to 80% of the matter in the universe. Its name refers to the fact it does not emit or interact with any type of electromagnetic radiation, being completely transparent throughout the electromagnetic spectrum.  

However, it interacts with the known matter through gravity.  

This means that, like gravity, dark matter can not be observed directly, however its existence is inferred through the movement of the stars and the cosmic dust within the galaxies.

Answer:

5- Normal, 68-dark energy, 27 dark matter

Explanation:

What is the correct composition of the universe, based on theoretical and cosmological observations?

   dark energy

   dark matter

   normal matter

   5 percent

   arrowRight

   68 percent

   arrowRight

   27 percent

   arrowRight

Answer:

The girl has greater tangential acceleration

Explanation:

The angular acceleration ([tex]\alpha[/tex]) of the merry go round is equal to the rate of the change of the angular velocity, [tex]\omega[/tex]:

[tex]\alpha = \frac{d\omega}{dt}[/tex]

Since all the points of the merry go round complete 1 circle in the same time, the angular velocity of each point of the merry go round is the same, and so all the points also have the same angular acceleration.

The tangential acceleration instead is given by

[tex]a_t = \alpha r[/tex]

where

[tex]\alpha[/tex] is the angular acceleration

r is the distance from the centre of the merry go round

Since the girl is near the outer edge and the boy is closer to the centre, the value of r for the girl is larger than for the boy, so the girl has greater tangential acceleration.

Answer: Tangential Velocity

The tangential velocity [tex]V[/tex] is defined as the angular velocity [tex]\omega[/tex] by the radius [tex]r[/tex] of circular motion. As shown below:

[tex]V=\omega. r[/tex]

Its name is due to the fact that this linear velocity vector is always tangent to the trajectory and is the distance traveled by a body or object in a circular movement in a period of time.

Final answer:

Using fossil fuels in thermal power stations has negative effects on the environment, causing pollution, greenhouse gas emissions, and resource depletion.

Explanation:

Using fossil fuels in thermal power stations has several negative aspects:

Environmental Toll: The extraction of fossil fuels can cause environmental damage, such as oil spills and contamination of water sources.

Air and Water Pollution: Burning fossil fuels releases harmful emissions like sulfur dioxide, nitrogen oxide, and mercury, leading to acid rain and smog.

Climate Change: Fossil fuel combustion results in the release of carbon dioxide, a greenhouse gas that contributes to global warming.

Resource Depletion and Cost: As fossil fuel reserves become harder to extract, their prices increase, leading to higher energy costs and potential resource conflicts.

The glacier retreats when the rate of forward motion of a glacier is slower than the rate of ablation

Answer: D

Explanation:

The Glacial ice moves with respect to the gravity, glacial ice always flows downwards in response to gravitational force and the front line of the glacier is either calving or melting into water which is also referred as shedding icebergs.

When the rate of flow of the glacier is quicker than the rate of melting or ablation, the advancing end of the glacier moves forward. Whereas, the rate of forward motion of the glacier is about the same as the rate of defrosting, the glacier edge doesn't intend to move at all, and if the rate of glacier's flow lacks behind the rate of defrosting, then it retreats (moves backward).

Answer:

Explanation:

The glacier retreats

Answer:

releasing the string

Explanation:

In a bow-arrow system, the potential energy stored by pulling the string backwards gets converted to kinetic energy when the string is released. Thus, more the string is pulled backwards, more potential energy would be stored. When the string is released, the potential energy reduces and converts to kinetic energy. Therefore, by releasing the string, the kinetic energy increases.

option A. Pulling back further on the bowstring increases the kinetic energy in the system. This is due to the added work, translated into kinetic energy when the string is released, accelerating the arrow to a higher speed.

The kinetic energy in this system will most likely increase by pulling farther back on the string. Kinetic energy is the energy of motion, and in this case, it's the energy that the arrow will have as it moves. When you pull back further on the bowstring, you are applying more work (force times distance) to the arrow. This additional work is transformed into kinetic energy when the string is released, causing the arrow to move at a higher speed, thus, the total kinetic energy of the arrow increases.

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I got 0.0126, but it feels wrong.

Answer:

+16 J

Explanation:

We can solve the problem by using the 1st law of thermodynamics:

[tex]\Delta U = Q-W[/tex]

where

[tex]\Delta U[/tex] is the change of the internal energy of the system

Q is the heat (positive if supplied to the system, negative if dissipated by the system)

W is the work done (positive if done by the system, negative if done by the surroundings on the system)

In this case we have:

Q = -12 J is the heat dissipated by the system

W = -28 J is the work done ON the system

Substituting into the equation, we find the change in internal energy of the system:

[tex]\Delta U=-12 J-(-28 J)=+16 J[/tex]

The light represents the sunlight.

The bottom of the box represents the surface of the Earth.

The air in the box represents the atmosphere.

The plastic wrap represents the part of the atmosphere where the Greenhouse gases are and influence the temperature.

So we have a box, air in it, plastic wrap, and directed light on it. The bottom of the box represents the surface of the Earth. The light that is directed towards it gets partially through the plastic wrap, reaching the bottom of the box and warming it up. As it warms up, the bottom of the box starts to radiate heat and returns it upwards through the air that represents the atmosphere. Then that heat reaches the plastic wrap, but it is not able to move through it, thus the air starts to warm up more and more, giving us a nice simplified example of how this process works.

Answer:  The new moon phase occurs when the Moon is directly between the Earth and Sun. A solar eclipse can only happen at new moon. A waxing crescent moon is when the Moon looks like crescent and the crescent increases ("waxes") in size from one day to the next. This phase is usually only seen in the west.

Answer: a new moon

Explanation:

when the moon is between the sun and the earth a new moon comes.

hope this helps btw this is correct

Answer:

-Parallel circuits have multiple branching pathways for electrical current.

-series circuit forms a single path.

The answer is A) specific chemical consumption

A should be the answer

Answer:

Parallel circuit

Explanation:

A parallel circuit is a closed circuit in which current flows and divide in two or more paths and recombining to complete the circuit, each load (light bulb) receives the fully voltage of the batteries in the circuit.