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3 years ago

Please help ASAP. There are 3 question it would be a big help if you can answer any.

Physics

2 answers:

sesenic [268]3 years ago

7 0

Answer:

number 1 is falling freely number 2 I think the 2nd option number 3 3rd option

erastova [34]3 years ago

7 0

1). If you're standing on a scale in an elevator, and the scale reads much less than your real weight, then the elevator must be accelerating downward.

(Think of the extreme limit: If the elevator is in free-fall, accelerating down at 9.8 m/s², then you'll apear to be weightless ... the scale will read zero.)

2). A 100 kg man is standing in an elevator, accelerating up at 2.0 m/s².

The net force acting on him is F = m·a = (100 kg) x (2.0 m/s²) = 200 N up.

The forces acting on him are:

-- gravity, m·g = (100 kg) x (9.8 m/s²) = 980 N down

-- elevator floor force . . . EF up

Net force = (980N down) + (EF up)

(200N up) = (980N down) + (EF up)

Add (980N up) to each side:

(200N up + 980N up) = EF up

Elevator force = 1180N up.

Pick the second choice: 1.2 x 10³ N up

3). My computer is resting on my desk.

There are many forces acting on my computer, and they are all balanced.

That means the NET force acting on my computer is zero.

If the net force were NOT zero, then my computer would be accelerating in the direction of the net force. But it's at rest. So the net force must be zero.

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At Hoover Dam, the distance the water effectively falls before encountering the electric generators depends on the water levels

pashok25 [27]

Answer:

Explanation:

recall that power is energy carried out or work done per time

P=W/t

P=2*10^6*35

t=6*60=420S

W=Energy

E=2*10^6*35*360S

E=25200000000

Energy stored by water from rest is called potential energy. Since the water is falling from a height , we calculate potential energy as thus

E=M*g*h

Assume that the water intakes are effectively 175 m above the electric generators. How much water must pass through the generators to power 2 million 35-W Las Vegas light bulbs for 6.0 minutes?

M=mass of water

g=acceleration due to gravity 9.81m/s^2

h=height ,175m

25200000000=M*9.81*175

M= $\frac{25200000000}{175*9.81}$

M=1716.75kg

3 0

3 years ago

Prob. 3: Manifestation of quantum phenomena (total 25 points) (a)-(e) 5 points each.

TEA [102]

Answer:

3A. This phenomenon can be seen in the discrete emission of the molecules.

3B. The emotion of the atoms is observed, from states high in energy to a state of minimum energy that is stable indefinitely.

3C. When an electron beam passes through an inhomogeneous magnetic field, it is divided into only two beams

3D. This is due to the stimulated emission

3E. The penetration of a potential barrier is observed in the radioactive emission of heavy atoms, where an alpha particle (Helium nucleus)

Explanation:

This problem asks for some experimental explanations of various quantum phenomena.

3A. This phenomenon can be seen in the discrete emission of the molecules.

In the classical explanation all states or energies are allowed, therefore when emitting energy (photons) there should be a continuum, this is not observed

In the correct quantum explanation only some states are allowed, therefore the emission must be discrete, which is observed in the emission or absorption of molecules and atoms

3B. The emotion of the atoms is observed, from states high in energy to a state of minimum energy that is stable indefinitely.

The incorrect classical explanation that if the minimum energy was zero the electrons cannot rotate around the nuclei and the atom collapses, this does not happen

3C. When an electron beam passes through an inhomogeneous magnetic field, it is divided into only two beams, which is evidence of the existence of two discrete states that we call spin, remember that a free electron beam has zero angular momentum.

3D. This is due to the stimulated emission that occurs when a photon passes through the emission zone, causing the atoms to have transitions and these emitted photons have the same initial photon location, the laser beam all photons are in phase and therefore it is coherent .

This is widely used for holographic and interference work

3E. The penetration of a potential barrier is observed in the radioactive emission of heavy atoms, where an alpha particle (Helium nucleus) leaves the atomic nucleus penetrating the barrier since its energy is lower than the nuclear barrier potential.

6 0

2 years ago

A 0.58 kg mass is moving horizontally with a speed of 6.0 m/s when it strikes a vertical wall. The mass rebounds with a speed of

Sunny_sXe [5.5K]

Answer:

$5.8\; {\rm kg\cdot m \cdot s^{-1}}$ .

Explanation:

If the mass of an object is $m$ and the velocity of that object is $v$ , the linear momentum of that object would be $m\, v$ .

Assume that the initial velocity of the mass is positive ( $6.0\; {\rm m\cdot s^{-1}}$ .) However, the direction of the velocity is reversed after the impact. Thus, the sign of the new velocity of the object would be negative- the opposite of that of the initial velocity. The new velocity would be $(-4.0\; {\rm m\cdot s^{-1}})$ .

Thus, the change in the velocity of the mass would be:

$\begin{aligned}& (\text{Change in Velocity}) \\ =\; & (\text{Final Velocity}) - (\text{Initial Velocity}) \\ =\; & (-4.0\; {\rm m\cdot s^{-1}}) - (6.0\; {\rm m\cdot s^{-1}}) \\ =\; & (-10\; {\rm m\cdot s^{-1})\end{aligned}$ .

The change in the linear momentum of the mass would be:

$\begin{aligned} & \text{change in momentum} \\ =\; & (\text{mass}) \times (\text{change in velocity}) \\ =\; & 0.58\; {\rm kg} \times (-10\; {\rm m\cdot s^{-1}}) \\ =\; & (-5.8\; {\rm kg \cdot m \cdot s^{-1}})\end{aligned}$ .

Thus, the magnitude of the change of the linear momentum would be $5.8\; {\rm kg \cdot m \cdot s^{-1}}$ .

7 0

2 years ago

The aorta pumps blood out of the heart to the rest of the body. Please select the best answer from the choices provided. T or f

Daniel [21]

The left ventricle relaxes and fills up with blood before squeezing and pumping the oxygen-rich blood through the aortic valve into the aorta — the main artery that carries blood to your body.TRUE

3 0

3 years ago

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Help Why does the sun move around the Milky Way galaxy

AnnyKZ [126]

It doesn't the sun stays still we move around the sun

5 0

3 years ago

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