Prove that in an elastic one-dimensional collision between two bodies, the relative velocity of approach before collision is equal to the relative velocity of separation after the collision. Hence derive expressions for the velocities of the two bodies in terms of their initial velocities before collision.
Answers
You have two questions here.
About elastic collision the momentum is conserved. Also the total KE of the system is conserved. Which means the KE of the colliding objects doesn't convert to other forms like heat or sound. But in reality it produces some heat or sound or both.
Keeping in mind these two conservation rules, if you calculate the velocities of the colliding objects, you will get an equation,
v1 - v2 = u2 - u1
Which means that the magnitude of the relative velocity of the objects remains the same but the direction will be reversed.
Now, about the second question, the xyz Volts, oone is the conductor in the transmission line on any equipment, to which the board refers and the other is ground. Which means if some one standing on the ground will get a shock of that dangerous potential. Birds sitting on the overhead lines don't get any shock because they don't come in contact with ground or the neutral condictor, at the same time.
Hope this helps.