Marvin lifts a box over his head. The work done on the box is- -Negative work -No work -Positive work

Physics

1 answer:

NemiM [27]2 years ago

6 0

Answer:

Positive work

Explanation:

When work and the exerted force are in the same direction, then the work done is positive.

In the question, we understand that Marvin lifts a box up (i.e. over his head). The force to lift the box acts in the upward direction and the work done itself is also in the upward direction (from the floor to Marvin's head).

Since these two are in the same direction, then we can conclude that the work done is positive.

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Two red and two overlapping balls in the center are surrounded by a green, fuzzy, circular cloud with a white line running throu

PolarNik [594]

Answer:

A. The line leading a bracket around the balls, labeled A, represents the nucleus of the atom.

B. The white line, labeled B, is signaling the first main energy level, as per the quantum model of the atom.

Explanation:

You are describing the model of an atom with two protons, two neutrons, the electron density (orbital), and two electrons.

Then, you want to know what the labels A and B represent.

The nucleus of the atom is at the center, where protons and neutrons are placed. This is supported by three models: Rutherford's model, Bohr's model, and the (currently accepted) quantum model.

Hence, the red balls and the two overlapping balls in the center are representing the protons and neutrons.

The line leading a bracket around the balls, labeled A, represents the nucleus of the atom, since it is signaling both protons and neutrons in the nucleus.

The green fuzzy circular cloud depicts the region where the electrons are: it is fuzzy in correspondence to the quantum model, which states the electrons are not in a fixed position but in a region around the atom. That region is named orbitals. As per the model you cannot tell the exact position of the electron, and that is what the fuzzy cloud means.

In the the Bohr's model that white line, which should be circular, where the electrons are, depicts the orbit of the electrons, and the shell, which were idenfified with letters L, M, N, K. The first shell was the L shell.

In the quantum model, that line corresponds to the principal quantum number n, which is the main energy level. Hence, the line leading to a bracket overlapping the white line depicts the main energy level.

The atom is neutral because it contains the same number of electrons aroud the nucleus as protons inside the nucleus.

3 0

3 years ago

Read 2 more answers

Compare the frequency, wavelength, and radiant energy of yellow visible light to that of purple visible light.

dybincka [34]

Answer:

Violet has a higher frequency (approximately 7.5×1014 Hz 7.5 × 10 14 Hz ) than red light (approximately 4.3×1014 Hz 4.3 × 10 14 Hz ). Since the speed of both waves is the same, we infer that violet has a shorter wavelength (400 nm ) than red (700 nm ).

Explanation:

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1 year ago

A semicircular plate with radius 6 m is submerged vertically in water so that the top is 2 m above the surface. Express the hydr

dalvyx [7]

Answer: 313920

Explanation:First, we’re going to assume that the top of the circular plate surface is 2 meters under the water. Next, we will set up the axis system so that the origin of the axis system is at the center of the plate.

Finally, we will again split up the plate into n horizontal strips each of width Δy and we’ll choose a point y∗ from each strip. Attached to this is a sketch of the set up.

The water’s surface is shown at the top of the sketch. Below the water’s surface is the circular plate and a standard xy-axis system is superimposed on the circle with the center of the circle at the origin of the axis system. It is shown that the distance from the water’s surface and the top of the plate is 6 meters and the distance from the water’s surface to the x-axis (and hence the center of the plate) is 8 meters.

The depth below the water surface of each strip is,

di = 8 − yi

and that in turn gives us the pressure on the strip,

Pi =ρgdi = 9810 (8−yi)

The area of each strip is,

Ai = 2√4− (yi) 2Δy

The hydrostatic force on each strip is,

Fi = Pi Ai=9810 (8−yi) (2) √4−(yi)² Δy

The total force on the plate is found on the attached image.