Ampere force F=BIL=? B2L2v 1r
According to the meaning of the question, there are: F=mgsinθ?
According to the kinetic energy theorem, the process of the wireframe sliding down the distance s is as follows: mgssinθ= 12mv 12.
Synthesize the above solutions: s=m2r22B4L4gsinθ=0.64m?
(2) In the whole process, according to the law of conservation of energy, there are:
Joule heat generated in the wire frame q = mg (h+12lsinθ) =13j.
(3) Let the speed of the wire frame just entering the horizontal guide rail be v2. In the whole process of the wire frame moving on the inclined track, according to the kinetic energy theorem, there are:
mg(h+ 12 lsinθ-2 lsinθ)= 12mv 2？
Solution: v2=6m/s?
After the wire frame enters the magnetic field of the horizontal guide rail, it decelerates until the speed drops to zero due to the ampere force. In the process of wireframe passing through any magnetic field region, according to the momentum theorem, there are: B.ILt=m△v, that is, BLq=m△v?
q =△φr q =△φr = 2 bl2r？
Therefore, when the wireframe passes through each magnetic field region, the speed decreases by the same amount, and △v=2B2L3mr?
The number of magnetic fields that the wireframe passes through on the horizontal guide rail.
n=v2？ 0△v=mrv22B2L3？ =2.4
The metal frame can pass through two complete magnetic field areas of the horizontal part of the guide rail.
Answer: (1) When the metal wire frame was first released, the distance s from the edge of MN to ab was 0.64m?
(2) The Joule heat generated in the whole process is 65438±03j.
(3) The wire frame can pass through two complete magnetic fields at the horizontal part of the guide rail.