Two positively charged particles X and Y are initially far away from each other and at rest. X begins to move towards Y with some initial velocity. The total momentum and energy of the system are p and E.
(A) If Y is fixed, both p and E are conserved.
(B) If Y is fixed, E is conserved, but not p.
(C) If both are free to move, p is conserved but not E.
(D) If both are free, E is conserved, but not p.
(A) If Y is fixed, both p and E are conserved.
(B) If Y is fixed, E is conserved, but not p.
(C) If both are free to move, p is conserved but not E.
(D) If both are free, E is conserved, but not p.
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This is a badly worded question , because it doesn't make clear what 'system' we are talking about. The fixed charge, Y, is attached to something (e.g. the earth); is the earth to be considered as part of the system?
Technically, if we say the system consists of X, Y and the rest of the universe, then the correct answer is (A).
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However, I think the question wants you to consider the system as being X and Y only. In this case:
(A) is false. Because Y is fixed, there is an external force acting on it, stopping it moving against the repulsion from X . Momentum is only conserved if no external force acts, so momentum is not conserved for X and Y.
(B) is true. Momentum won't be conserved because of the external force holding Y. But no overall energy will be lost - the ke lost will equal the electrical potential energy gained. A bit like compressing a spring with one end fixed.
(C) and (D) are false. If X and Y were free to move (and have no external forces acting on them), then E and p would both be conserved.
Hope that helps.
Hope that helps.
Technically, if we say the system consists of X, Y and the rest of the universe, then the correct answer is (A).
______________________________________…
However, I think the question wants you to consider the system as being X and Y only. In this case:
(A) is false. Because Y is fixed, there is an external force acting on it, stopping it moving against the repulsion from X . Momentum is only conserved if no external force acts, so momentum is not conserved for X and Y.
(B) is true. Momentum won't be conserved because of the external force holding Y. But no overall energy will be lost - the ke lost will equal the electrical potential energy gained. A bit like compressing a spring with one end fixed.
(C) and (D) are false. If X and Y were free to move (and have no external forces acting on them), then E and p would both be conserved.
Hope that helps.
Hope that helps.
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All charged particles move .Nothing is at rest in the Universe
The total energy of a system is conserved
when a charged particle loses mass its motion al energy is conserved. Thus all charged particles have the same energy of motion but not necessarily their intrinsic mass.
The mass of a proton is 1815 bigger than the mass of an electron and both are charged particles. momentum indicated that a charged particle moves at a particular velocity.
Inside the atom the angular momentum of an electron is a constant.
The total energy of a system is conserved
when a charged particle loses mass its motion al energy is conserved. Thus all charged particles have the same energy of motion but not necessarily their intrinsic mass.
The mass of a proton is 1815 bigger than the mass of an electron and both are charged particles. momentum indicated that a charged particle moves at a particular velocity.
Inside the atom the angular momentum of an electron is a constant.