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Dima020 [189]
3 years ago
10

What is spontaneous emission?

Physics
2 answers:
Oxana [17]3 years ago
5 0

Answer:

Spontaneous emission is  a quantum effect, which in a semiclassical picture can be described as an emission which is stimulated by vacuum noise.

Irina-Kira [14]3 years ago
4 0

Spontaneous emission is the process in which a quantum mechanical system transits from an excited energy state to a lower energy state and emits a quantized amount of energy in the form of a photon. <em><u>definition from wikipedia </u></em>

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A spherical asteroid of average density would have a mass of 8.7×1013kg if its radius were 2.0 km. 1. If you and your spacesuit
Law Incorporation [45]

1. 0.16 N

The weight of a man on the surface of asteroid is equal to the gravitational force exerted on the man:

F=G\frac{Mm}{r^2}

where

G is the gravitational constant

M=8.7\cdot 10^{13}kg is the mass of the asteroid

m = 100 kg is the mass of the man

r = 2.0 km = 2000 m is the distance of the man from the centre of the asteroid

Substituting, we find

F=(6.67\cdot 10^{-11}m^3 kg^{-1} s^{-2})\frac{(8.7\cdot 10^{13} kg)(110 kg)}{(2000 m)^2}=0.16 N

2. 1.7 m/s

In order to stay in orbit just above the surface of the asteroid (so, at a distance r=2000 m from its centre), the gravitational force must be equal to the centripetal force

m\frac{v^2}{r}=G\frac{Mm}{r^2}

where v is the minimum speed required to stay in orbit.

Re-arranging the equation and solving for v, we find:

v=\sqrt{\frac{GM}{r}}=\sqrt{\frac{(6.67\cdot 10^{-11} m^3 kg^{-1} s^{-2})(8.7\cdot 10^{13} kg)}{2000 m}}=1.7 m/s

3 0
3 years ago
Does Ap Physics have anything to do with probablity?
padilas [110]
So I'm a junior. I am currently taking AP Calc BC and AP Physics B.

As of now, I'm not sure if I should take AP Probability and Statistics or Differential Equations/Calc III next year. Also, I'm debating between taking AP Physics C or AP Chemistry.

Which ones do you think would look better on a transcript? I heard that Diffeq/CalcIII is harder than AP ProbStat, but ProbStat is an AP course which will be weighted heavier. Also, should I take Physics C since i've taken Physics B this year already?
5 0
3 years ago
A car starts from rest and drives at 45 m/s in 20 s. how far did it travel
Schach [20]

Answer:

distance=speed×time.

45×20=900m.

6 0
3 years ago
What is the change in momentum of a 50-kg rock that falls freely for 3 seconds?
Elan Coil [88]

Answer:

1470kgm/s

Explanation:

Given parameters:

Mass of the rock = 50kg

Time taken for the free fall  = 3s

Unknown:

Change in momentum = ?

Solution:

The change in momentum will be difference between the ending momentum and finishing momentum.

  Momentum is the product of mass and velocity

       Momentum  = mass x velocity

Initial momentum  = 0, the velocity is 0

Final momentum = mass x final velocity

      let us find the final velocity;

                V = U + gt

V is the final velocity

U is the initial velocity

g is the acceleration due to gravity = 9.8m/s²

t is the time

                 V  = 0 + 9.8x3 = 29.4m/s

So;

 Change in momentum  = 50 x 29,4  = 1470kgm/s

6 0
2 years ago
Sam is riding his bike in the park when he sees a soccer ball rolling toward him. He applies his brakes to slow down. Once he st
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When Sam presses the brake lever, a pair of rubber shoes  clamps onto the metal inner rim of the front and back wheels. As the brake shoes rub  against the wheels, friction is caused and  the kinetic energy possessed by the vehicle is converted into heat which slows down the vehicle.

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2 years ago
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