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3 years ago

8

A golf ball is projected at an angle of 30 degrees to the ground. If velocity of the object is 20 m/s, calculate the horizontal

component of this velocity

1 answer:

alex41 [277]3 years ago

4 0

Answer: 17.3

Explanation:

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Lawson's criterion states that the product of ion density and confinement time must exceed a certain number before a break-even

LekaFEV [45]

According to Lawson's criterion, the outcome is determined by the product of ion density and confinement time because the temperature must be maintained for a sufficient confinement time and with a sufficient ion thickness to obtain a net gain of power from a fusion reaction.

<h3>What are Lawson's criterion?</h3>

The overall conditions that must be met in order to produce more energy than is required for plasma heating are usually expressed in terms of the product of ion density and confinement time, a condition known as Lawson's criterion.

In nuclear fusion devices, confinement time is defined as the amount of time the plasma is kept at a temperature above the critical ignition temperature.

Even at temperatures high enough to overcome the coulomb barrier to nuclear fusion, a critical density of ions must be maintained in order to achieve a net yield of energy from the reaction.

Because the density required for a net energy yield is correlated with the confinement time for hot plasma, the minimum condition for a productive fusion reaction is typically stated in terms of the product of ion density and confinement time, which is known as Lawson's criterion.

To learn more about Lawson's criterion, refer:

brainly.com/question/28303495

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7 0

1 year ago

Why the object will not return to its original position?<br>why does the centre of mass fall?

dusya [7]

Answer:

the object will not return to the original position because it will not have any forces helping it to go up the hill

the center of mass falls since it is going downwards

Hope this helps!! have a great day

Explanation:

8 0

4 years ago

The following table lists the work functions of a few common metals, measured in electron volts. Metal Φ(eV) Cesium 1.9 Potassiu

Citrus2011 [14]

A. Lithium

The equation for the photoelectric effect is:

$E=\phi + K$

where

$E=\frac{hc}{\lambda}$ is the energy of the incident light, with h being the Planck constant, c being the speed of light, and $\lambda$ being the wavelength

$\phi$ is the work function of the metal (the minimum energy needed to extract one photoelectron from the surface of the metal)

K is the maximum kinetic energy of the photoelectron

In this problem, we have

$\lambda=190 nm=1.9\cdot 10^{-7}m$ , so the energy of the incident light is

$E=\frac{hc}{\lambda}=\frac{(6.63\cdot 10^{-34}Js)(3\cdot 10^8 m/s)}{1.9\cdot 10^{-7} m}=1.05\cdot 10^{-18}J$

Converting in electronvolts,

$E=\frac{1.05\cdot 10^{-18}J}{1.6\cdot 10^{-19} J/eV}=6.5 eV$

Since the electrons are emitted from the surface with a maximum kinetic energy of

K = 4.0 eV

The work function of this metal is

$\phi = E-K=6.5 eV-4.0 eV=2.5 eV$

So, the metal is Lithium.

B. cesium, potassium, sodium

The wavelength of green light is

$\lambda=510 nm=5.1\cdot 10^{-7} m$

So its energy is

$E=\frac{hc}{\lambda}=\frac{(6.63\cdot 10^{-34}Js)(3\cdot 10^8 m/s)}{5.1\cdot 10^{-7} m}=3.9\cdot 10^{-19}J$

Converting in electronvolts,

$E=\frac{3.9\cdot 10^{-19}J}{1.6\cdot 10^{-19} J/eV}=2.4 eV$

So, all the metals that have work function smaller than this value will be able to emit photoelectrons, so:

Cesium

Potassium

Sodium

C. 4.9 eV

In this case, we have

- Copper work function: $\phi = 4.5 eV$

- Maximum kinetic energy of the emitted electrons: K = 2.7 eV

So, the energy of the incident light is

$E=\phi+K=4.5 eV+2.7 eV=7.2 eV$

Then the copper is replaced with sodium, which has work function of

$\phi = 2.3 eV$

So, if the same light shine on sodium, then the maximum kinetic energy of the emitted electrons will be

$K=E-\phi = 7.2 eV-2.3 eV=4.9 eV$

7 0

4 years ago

A hot-air balloon is floating above a straight road. To estimate their height above the ground, the balloonists simultaneously m

ki77a [65]

We know that
tan(∅) = y/x; where y will be the height of the balloon and x will be the distance from the milestone marker.
The marker that is further away will produce a smaller angle of depression.
tan(18) = height / x
x = height / tan(18)

The second marker is x + 1 miles away:
tan(16) = height / x + 1; substituting x:
tan(16) = height / (height/tan(18) + 1)
tan(16) x [(height / tan(18) + 1] = height
0.88h + 0.29 = h
h = 2.42 miles

8 0

3 years ago

A potassium atom (atomic number 19) and a bromine atom (atomic number 35) can form a chemical bond through a transfer of one ele

Nookie1986 [14]

Answer:

it will give one electron to the bromine atom, so the bromine atom will have 36 electrons. this is an ionic bonding

Explanation:

3 0

3 years ago