A bar magnet is used to pick up an iron nail at which part p, q and r is the easiest for the magnet to pick up the iron nail? A) at p b) at q c) at r d) it makes no difference at any part
Answers
Answer:
height hhit the ground with velocity v. This velocity can be calculated by Law and equating loss of potential Conservation of energy=mgh to gain in kinetic energy =12mv2.
As mgh=12mv2
⇒h=v22g .......(1)
The coefficient of restitution of collision between the ground and body is given as e.
Therefore, the body bounces back with velocity =v×e
Distance traveled =h ......(2)
Let the object now go up against gravity say up to height =h1
Thereafter it drops to the ground under gravity and rebounds with velocity =ve
From law of Conservation of energy
mgh1=12m(ve)2
⇒h1=(ve)22g
Using (1)
⇒h1=e2h
Distance traveled =2h1=2e2h ......(3)
And the body bounces back with velocity =(ve)×e=ve2
This goes on. As such with each bounce the distance traveled is sum of successive terms
d=h+2e2h+(2e2h)×e2+(2e4h)×e2.........
For the object to come to rest it is sum of infinite series
d=h+2e2h(1+e2+e4+e6+.........................)
⇒d=h[1+2e2(1+e2+e4+e6+.........................)]
For e<1, the series (1+e2+e4+e6+.........................)converges to 11−e2, and we get
d=h[1+2e21−e2]
⇒d=h[1−e2+2e21−e:
Answer:
Answer is C) At r it will be easy for the magnet to pick up the iron nail