Result:
, 
Explanation:
The electromagnetic attraction between the electron and the proton in the nucleus is equivalent to the centripetal force:

where
k represents the Coulomb constant
e denotes the charge of the electron
e denotes the charge of the proton in the nucleus
r signifies the distance from the electron to the nucleus
v indicates the velocity of the electron
is the mass of the electron
Rearranging for v, we determine

Inside a hydrogen atom, the distance separating the electron from the nucleus is roughly

while the mass of the electron is

and the charge is

By plugging in the values into the formula, we achieve

For this issue, the answer is clarified as the system takes in energy (+). The surroundings contribute 84 KJ of work. Whenever a system is receiving work from its surroundings, the value will be positive. Therefore, it sums to 12.4 KJ + 4.2 = 16.6 KJ.
Answer:3.87*10^-4
Explanation:
To determine the mass reduction, delta mass Xe, of the xenon nucleus due to its decay, we first use the provided wavelength of the gamma radiation to calculate its frequency via c = freq*wavelength.
From C=f*lambda we set up: 3*10^8=f*3.44*10^-12.
Solving gives frequency F=0.87*10^20 Hz.
Next, we calculate the emitted energy using the equation E=hf, which translates to E=f*Planck's constant.
Thus, E=0.87*10^20*6.62*10^-34, resulting in E=575.94*10^(-16).
This energy is then converted from joules to MeV.
Utilizing the formula E=mc^2, with c^2 = 931.5 MeV/u, enables us to find the reduction in mass, yielding
3.87*10^-4 u.
Answer: t = 0.878s
Explanation: A note for you,
since the temperature decreases in a straight line, you can expect the movement speed to also behave linearly. However, this isn't exactly true (referring to the formula). Alternatively, utilize the interpolation principle: (x/v_surface + x/v_top)/2 = t.
While the answer may not match exactly, it should be a close approximation. You can use this formula, thus avoiding large distance calculations.