Marisa's car accelerates at an average rate of 2.6m/s2. How long will it take her car to accelerate from 24.6m/s to 26.8m/s?

Speed up and spread apart

Final answer:

Iron melting is an example of a physical change because it involves a state change without altering the substance's chemical composition.

Explanation:

An example of a physical change from the options provided is iron melting. Physical changes are characterized by a change in the state or properties of matter without altering its chemical composition. When iron melts, it changes from solid to liquid, but the substance remains iron; its molecules are not changed. Other examples of physical changes might include boiling water, dissolving sugar in water, or breaking a mirror. Conversely, wood decaying, paper burning, and steel rusting involve chemical reactions that create new substances, thus, they are chemical changes.

Answer:

c

Explanation:

Final answer:

The minimum value of the force needed to move the two blocks is approximately 27.93 N.

Explanation:

To determine the minimum value of the force needed to move the two blocks, we need to consider the friction between the blocks and the surface. Since the coefficient of static friction is given, we can use it to find the maximum static friction force:

Fstatic_max = μstatic × N

where μstatic is the coefficient of static friction and N is the normal force. Since the 3.0-kg block is sitting on top of the 5.0-kg block, the normal force on the 5.0-kg block is equal to its weight:

N = m × g

where m is the mass of the 5.0-kg block and g is the acceleration due to gravity. Once the force F is greater than the maximum static friction force, the blocks will begin to move. The minimum value of F needed to move the two blocks is therefore equal to the maximum static friction force:

F = Fstatic_max

Substituting the given values, the equation becomes:

F = μstatic × (m × g)

Plugging in the values, we get:

F = 0.57 × (5.0 kg × 9.8 m/s²)

Simplifying, we find that the minimum value of F needed to move the two blocks is approximately 27.93 N.

Magnetism is a force that can attract "pull toward" or repel "push away" some materials. Certain elements such as cobalt, iron, and nickel. are strongly attracted by a magnetic force and are called ferromagnetic.

A magnetic field is the area of space around a magnet where magnetism is detected. The poles are where the magnetic field is the strongest. The larger the magnet, the greater its magnetic field is.

The density of a mineral sample with a volume of 4 ml and a mass of 20 grams is 5 grams per milliliter (g/ml).

If you have a mineral sample with a volume of 4 ml and a mass of 20 grams, the density can be calculated using the formula:

Density = Mass / Volume

Substituting the given values into the formula, we get:

Density = 20 grams / 4 ml = 5 grams per milliliter (g/ml).

Answer: B convection

Explanation: cause :)

Final answer:

The primary heat transfer mechanism in liquids and gases is convection, which involves the movement of the fluid itself to transport heat. Conduction and radiation are the other two methods of heat transfer, with conduction involving direct contact and radiation involving electromagnetic waves.

Explanation:

The main type of heat transfer in liquids and gases is convection. Convection is the heat transfer by the macroscopic movement of a fluid, such as water or air. This process involves the circulation or movement of the fluid itself, which carries heat from one place to another. An example of convection in action is the way warm air rises and cool air falls, setting up a cycle that distributes heat throughout a room.

Heat transfer can also occur through conduction when heat is transferred through direct contact between materials, and radiation, which is the transfer of energy by electromagnetic waves and does not require a medium. These are the three fundamental methods of heat transfer: convection, conduction, and radiation.

Answer:

The law of refraction states that the incident ray, the refracted ray, and the normal to the interface, all lie in the same plane.

Explanation:

Answer:

1 ) angle of incidence is always equal to the angle of reflection

2) the incidence ray , the normal at the point of incidence and the reflection ray , all lie in the same plane

Answer:a

Explanation:

took quiz

acts at a distance

is the answer

Answer:

Gravitational force is a non-contact force.

Explanation:

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An increase in potential energy in a system where kinetic energy remains constant leads to an overall increase in the system's internal energy. This conservation of mechanical energy illustrates the exchange between potential and kinetic energy without an overall energy increase, provided there are no energy losses such as friction.

When the potential energy in a system is said to increase while the kinetic energy remains equal to the original potential energy, the total internal energy of the system increases. If there is a net transfer of energy into the system and the macroscopic mechanical energy—like overall speed and elevation—does not change, then this increase in energy is attributed to a rise in the system's internal potential energy or internal kinetic energy, or a combination of both.

Gravitational potential energy increases as an object is moved higher from the surface of the Earth, as the force of gravity does negative work. This potential energy is then available to be converted back into kinetic energy, as seen when an object falls back towards the Earth, picking up speed and thus kinetic energy, as it descends.

In cases where the system is not isolated, an input of energy can lead to an increase in the system's mass, according to the principle that mass and energy are equivalent. Moreover, in the absence of external forces like friction, the mechanical energy of the system remains constant, with a conversion between kinetic and potential energy, but not an overall increase.

When the potential energy in a system increases to be equal to the kinetic energy, this indicates a transfer of energy within the system where the internal potential energy is rising. This increase in potential energy is often associated with the separation of particles, leading to an eventual rise in energy.

The increase in internal energy can result in a rise in temperature, or it can manifest as an increase in the potential energy of the system. Mathematically, the potential energy rises as particles move farther apart until it reaches a maximum value of zero.

Answer:

Option D is right

Explanation:

Mixture is defined as a combination of different things in which the component elements are individually distinct.

i.e. only physically they are mixed and each substance retains its original characteristic even after mixing.  For mixing, no heating or any other mode is required.

Hence out of the 4 option I option is not right since dissolution makes losing characteristic

B) is wrong since molecules cannot break down in physical mixing

C) is wrong as single mixture will have same characteristic

D) Is right One substance can be separated from another through physical means

Answer:  D)  One substance can be separated from another through physical means.

Explanation:

Have a wonderfullllll day:)

From our physics class, we know that Work is a product of Force and Displacement. The force must be the force in the same direction with the displacement. So force and displacement must be parallel.

A. How much work in J does the string do on the boy if the boy stands still?

Since we know that: Work = Force * Displacement

and in this case displacement is equal to zero, therefore Work must also be equal to zero.

Work = 0

B. How much work does the string do on the boy if the boy walks a horizontal distance of 11m away from the kite?

Now are given a displacement of 11 m which is a horizontal distance. Therefore we must first calculate the horizontal component of force:

Fx = 4.5 N * cos 30

Fx = 3.897 N

So work is:

Work = 3.897 N * 11 m

Work = 42.87 J ~ 43 J

The string does 49.5J of work on the boy when he stands still, -49.5J when he walks away from the kite, and 49.5J when he walks toward the kite.

The work done by the tension in the string on the boy can be calculated using the formula:

Work = Force * Distance * cos(θ)

where θ is the angle between the force vector and the displacement vector. In this case, the tension force is acting horizontally, so the angle between the force and displacement vectors is 0 degrees.

Therefore, for the first scenario (boy standing still), the work done by the string is:Work = 4.5N * 11m * cos(0°)

Since cos(0°) = 1, the work done by the string is:Work = 4.5N * 11m * 1 = 49.5J

In the second scenario (boy walking away from the kite), the displacement vector is in the opposite direction of the tension force, so the angle between them is 180 degrees.

Therefore, the work done by the string is:Work = 4.5N * 11m * cos(180°)

Since cos(180°) = -1, the work done by the string is:Work = 4.5N * 11m * -1 = -49.5J

In the third scenario (boy walking toward the kite), the displacement vector is aligned with the tension force, so the angle between them is 0 degrees.

Therefore, the work done by the string is:Work = 4.5N * 11m * cos(0°)

Since cos(0°) = 1, the work done by the string is:Work = 4.5N * 11m * 1 = 49.5J

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Oxygen (C) is the element among the given options. It is a pure substance found on the periodic table as 'O', while the other choices are compounds consisting of various elements combined.

The question which of the following is an element? A. Water B. Carbon Dioxide C. Oxygen D. Ammonia - requires identifying the pure element from a list that includes compounds. An element is a substance that consists of only one type of atom, whereas a compound is a substance made from more than one type of atom joined by chemical bonds.

Out of the given options, Oxygen (C) is the correct answer. Oxygen is an element that is listed on the periodic table as 'O'. It is also one of the seven diatomic molecular elements, meaning it's commonly found as two atoms of oxygen bonded together (O₂). In contrast, water (H₂O), carbon dioxide (CO₂), and ammonia (NH₃) are compounds made up of hydrogen, carbon, and nitrogen atoms joined with oxygen in different combinations.