.(क) निम्न में से किस मीटर का प्रतिरोध उच्चतम होता है:

How many neutrons does element X if it’s atomic number is 28 and its mass number is 87

Sergeeva-Olga [200]

the answer is 59 neutrons

7 0

3 years ago

A race car starting from rest accelerates uniformly at a rate of 4.90 meters per squared. What is the cars speed after it has tr

shusha [124]

Ok, we need to find a relation for the speed as it relates to the acceleration. This is given by the integral of acceleration:

$v= \int\limits^{t}_{0} {a} \, dt' =at$

Where we have the initial velocity is 0m/s and a will be 4.90m/s².

But we see there is an issue now... We know the velocity as a function of time, but we don't know how long the car has been accelerating! We need to calculate this time by now finding the position function as a function of time. This way we can solve for the time, t, that it takes to go 200m accelerating this way and then substitute that time into our velocity equation and get the velocity.
Position is just the integral of velocity:

$s= \int\limits^{}_{} {at} \, dt = \frac{1}{2}at^2$

Where the initial velocity and initial position are both zero.

Now we set this position function equal to 200m and find the time, t, it took to get there

$\frac{1}{2}(a \frac{m}{s^2} )t^2=200m \\ \\ \frac{1}{2}4.90 \frac{m}{s^2} t^2=200m \\ \\ t^2= \frac{400m}{4.90 \frac{m}{s^2}}=81.63s^2 \\ \\ t= \sqrt{81.63s^2 } =9.04s$

Now let's put t=9.04s into our velocity equation:

$v =at=4.9\frac{m}{s^2} \times 9.04s=44.3 \frac{m}{s}$

8 0

3 years ago

Please help,,, question on image

MA_775_DIABLO [31]

Answer:

first you have to

Explanation:

3 0

3 years ago

The latent heat of vaporization for water at room temperature is 2430 J/g.

alukav5142 [94]

Answer:

1) $kinectic energy=7.26*10^-^2^0J$

2) $V= 2.0m/s$

3) $T=3.5*10^3K$

4) The Molecules do not burn because of the presences of hydrogen bond in place

Explanation:

From the question we are told that

latent heat of vaporization for water at room temperature is 2430 J/g.

1)Generally in determining the molar mass of water evaporated we have that

-One mole (6.02 x 10. 23 molecules)

-Molar mass of water is 18.02 g/mol

Mathematically the mass of water is give as

$M=\frac{18.02}{6.02*10^-^2^6}$

$M=3*10^-^2^3g$

Therefore

$kinectic energy=2430J/g*3*10^-^2^3g$

$kinectic energy=7.26*10^-^2^0J$

b)Generally the evaporation speed V is given as $V= \sqrt{\frac{K.E*2}{m} }$

Mathematically derived from the equation

$\frac{1}{2} mv^2 =K.E$

To Give

$V= \sqrt{\frac{K.E*2}{m} }$

$V= \sqrt{\frac{7.26*10^-^2^0J*2}{3*10^-^2^3g} }$

$V= 2.0m/s$

c)Generally the equation for velocity $Vrms=\sqrt{\frac{3RT}{M} }$

Therefore

Effective temperature T is given by

$T=\frac{\sqrt{v}*m}{R}$

where

$T=\frac{\sqrt{2.0m/s}*6.02*10^-^2^6}{0.082057 L atm mol-1K-1}$

$T=3.5*10^3K$

4) The Molecules do not burn because of the presences of hydrogen bond in place

3 0

3 years ago

How and why does breathing rate increase during exercise

kondor19780726 [428]

<span>Your heart speeds up to pump extra food and oxygen to the muscles. Breathing speeds up to get more oxygen and to get rid of more carbon dioxide. When a fit person, such as an athlete, exercises the pulse rate, breathing rate and lactic acid levels rise much less than they do in an unfit person.
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7 0

4 years ago