How much force is needed to accelerate a 66kg skier at 2m/s

Oxygen makes up more than 90 percent of the volume of the Earth's crust. Is oxygen found as a solid, liquid, or gas?

kipiarov [429]

Answer:

Oxygen is an element that can be a solid, liquid or gas depending on its temperature and pressure. In the atmosphere it is found as a gas, more specifically, a diatomic gas. This means that two oxygen atoms are connected together in a covalent double bond.

5 0

3 years ago

in an exothermic chemical reaction the energy gained by the surroundings must be _______ the energy lost by the reaction

Yuliya22 [10]

Answer:

In an exothermic reaction the energy gained by the surroundings must be equal to the energy lost by the reaction.

Explanation:

Exothermic reactions occur by the loss of energy in the form of heat to the surroundings (apparatus and the system).

The heat gained can be quantitatively analysed and measured provided no product escapes the system and it is numerically equal to the amount of heat lost by the reaction.

4 0

3 years ago

An electron is projected with an initial speed vi = 4.60 × 105 m/s directly toward a very distant proton that is at rest. Becaus

frutty [35]

Answer:

$2.99\times 10^{-19}\ m$

Explanation:

Given:

$u$ = initial velocity of the electron = $4.60\times 10^5\ m/s$

$v$ = final velocity of the electron = $3u$

$x$ = initial position of the electron from the proton = very distant = $\infty$

Assume:

$m$ = mass of an electron = $9.1\times10^{-31}\ kg$

$e$ = magnitude of charge on an electron = $1.6\times10^{-19}\ C$

$p$ = magnitude of charge on an proton = $1.6\times10^{-19}\ C$

$k$ = Boltzmann constant = $9\times 10^9\ Nm^2/C^2$

$y$ = final position of the electron from the proton

$\Delta K$ = change in kinetic energy of the electron

$W$ = work done by the electrostatic force

$F$ = electrostatic force

$r$ = instantaneous distance of the electron from the proton

Let us first calculate the work done by the electrostatic force.

$W=\int Fdr\\\Rightarrow W = \int \dfrac{kep}{r^2}dr\\\Rightarrow W = kep\int \dfrac{1}{r^2}dr\\\Rightarrow W = kep\left | \dfrac{1}{r} \right |_{y}^{x}\\\Rightarrow W = kep\left ( \dfrac{1}{x}-\dfrac{1}{y} \right )\\\Rightarrow W = kep\left ( \dfrac{1}{x}-\dfrac{1}{\infty} \right )\\\Rightarrow W =\dfrac{kep}{x}$

Using the principle of the work-energy theorem,

As only the electrostatic force is assumed to act between the two charges, the kinetic energy change of the electron will be equal to the work done by the electrostatic force on the electron due to proton.

$\therefore \Delta K = W\\\Rightarrow \dfrac{1}{2}m(v^2-u^2)= \dfrac{kep}{x}\\\Rightarrow \dfrac{1}{2}m((3u)^2-u^2)= \dfrac{kep}{x}\\\Rightarrow \dfrac{1}{2}m(8u^2)= \dfrac{kep}{x}\\\Rightarrow x= \dfrac{2kep}{8mu^2}\\\Rightarrow x= \dfrac{2\times 9\times 10^9\times 1.6\times10^{-19}\times 1.6\times10^{-19}}{8\times 9.1\times10^{-31}\times (4.60\times 10^5)^2}\\\Rightarrow x=2.99\times 10^{-10}\ m\leq$

Hence, the electron is at a distance of $2.99\times 10^{-10}\ m$ when the electron instantaneously has speed of three times the initial speed.

8 0

4 years ago

A gas bottle contains 7.86×10^23 Oxygen molecules at a temperature of 327.0 K.

castortr0y [4]

Answer:

1. E=5320.3J

2. E= 1773.45J

3. E=6.76*10^{-21}J

4. E=2.25*10^{-21}J

Explanation:

1. the thermal energy is given by the formula

$E_T=\frac{3}{2}NK_BT=\frac{3}{2}(7.86*10^{23})(1.38*10^{-23}\frac{J}{K})(327.0K)=5320.3J$

where KB is the Boltzmann's constant, T is the temperature and N is the number of molecules in the system.

2. Each degree of freedom contains one half of the total energy. Hence, the energy for one degree of freedom is

$E_1=\frac{1}{2}NK_BT=1773.45J$

3.

$E=\frac{3}{2}K_BT=6.76*10^{-21}J$

4.

$E=\frac{1}{2}K_BT=2.25*10^{-21}J$

Hope this helps!!

6 0

3 years ago

The transfer of thermal energy is a major aspect of which branch of physics?

scZoUnD [109]

Mechanics is dealing with forces that are effecting some body, electrostatics is about electrical fields of not moving bodies, and quantum mechanics is dealing with quantum states of atoms.

Thermodynamics as the word say, is dealing with thermal energy that is moving (transferring from one body to another or even better from one medium to another).

Answer is C

3 0

4 years ago

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