Answer:
a) The proton's speed is 5.75x10⁵ m/s.
b) The kinetic energy of the proton is 1723 eV.
Explanation:
a) The proton's speed can be calculated with the Lorentz force equation:
(1)
Where:
F: is the force = 9.14x10⁻¹⁷ N
q: is the charge of the particle (proton) = 1.602x10⁻¹⁹ C
v: is the proton's speed =?
B: is the magnetic field = 3.28 mT
θ: is the angle between the proton's speed and the magnetic field = 17.6°
By solving equation (1) for v we have:

Hence, the proton's speed is 5.75x10⁵ m/s.
b) Its kinetic energy (K) is given by:

Where:
m: is the mass of the proton = 1.67x10⁻²⁷ kg
Therefore, the kinetic energy of the proton is 1723 eV.
I hope it helps you!
Answer:
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Answer:
Option B. Decreases
Explanation:
Coulomb's law states that:
F = Kq₁q₂ / r²
Where:
F => is the force of attraction between two charges
K => is the electrical constant.
q₁ and q₂ => are the two charges
r => is the distance apart.
From the formula:
F = Kq₁q₂ / r²
The force of attraction (F) is inversely proportional to the square of their separating distance (r).
This implies that as the distance between them increase, the force of attraction between the two charges will decrease and as the distance between two charges decrease, the force of attraction between them will increase.
Considering the question given above and the illustration given above, the force of attraction will decrease as their distance of separation increases.
Option B gives the right answer to the question.
Answer:
Option B
Change in entropy of the process is 
Explanation:
The entropy of a system is a measure of the degree of disorderliness of the system.
The entropy of a system moving from process 1 to 2 is given as

recall from first law, 
hence we have, 
since the process is isothermal, 
this gives us 
integrating within the limits of 1 and 2, will give us

also from ideal gas laws,
hence we have 
This makes the correct option B
Explanation:
They probably put "rolls without slipping" in there to indicate that there is no loss in friction; or that the friction is constant throughout the movement of the disk. So it's more of a contingency part of the explanation of the problem.
(Remember how earlier on in Physics lessons, we see "ignore friction" written into problems; it just removes the "What about [ ]?" question for anyone who might ask.)
In this case, you can't ignore friction because the disk wouldn't roll without it.
As far as friction producing a torque... I would say that friction is a result of the torque in this case. And because the point of contact is, presumably, the ground, the friction is tangential to the disk. Meaning the friction is linear and has no angular component.
(You could probably argue that by Newton's 3rd Law there should be some opposing torque, but I think that's outside of the scope of this problem.)
Hopefully this helps clear up the misunderstanding for you.