In the real universe, no black holes contain singularities. In general, singularities are the non-physical mathematical result of a flawed physical theory.
First of all, let's just talk about the speed, and not get wound up
in the velocity. OK ?
If a fly is sitting on the rim of the wheel and the wheel is rotating, then for
each full revolution of the wheel, the fly travels the circumference of the
wheel, which is (2 π) x (radius of the wheel).
In 'N' revolutions, the fly travels (2 N π) x (the radius). and so on.
So if the wheel is going, let's say 71 revs per minute (RPM), a point
on the rim is moving at (2 π times 71) x (the radius) per minute.
Another way to say it:
Speed of a point on the circle = (2 π) x (rotation frequency) x (radius).
The 'rotation frequency' takes care of the unit of time, and the 'radius'
takes care of the unit of length, so the result is a speed.
3.5 seconds is 3500 milliseconds.
Explanation:
It is given that,
Velocity of the electron, 
Magnetic field, 
Charge of electron, 
(a) Let 
is the force on the electron due to the magnetic field. The magnetic force acting on it is given by :
![F_e=1.6\times 10^{-19}\times [(2\times 10^6i+3\times 10^6j)\times (0.030i-0.15j)]](https://tex.z-dn.net/?f=F_e%3D1.6%5Ctimes%2010%5E%7B-19%7D%5Ctimes%20%5B%282%5Ctimes%2010%5E6i%2B3%5Ctimes%2010%5E6j%29%5Ctimes%20%280.030i-0.15j%29%5D)
(b) The charge of electron, 
The force acting on the proton is same as force on electron but in opposite direction i.e (-k). Hence, this is the required solution.
Answer:
b) -10 m/s
Explanation:
In perfectly elastic head on collisions of identical masses, the velocities are exchanged with one another.
