Two masses collide and stick together. Before the collision, one ...

[kfurse]

Two masses collide and stick together. Before the collision, one of the masses was at rest. Is there a situation in which the kinetic energy is conserved in such a collision?
 a. Yes, if the less massive particle is the one initially at rest.
  b. Yes, if the more massive particle is the one initially at rest.
  c. Yes, if the two particles have the same mass.
  d. No, kinetic energy is always lost is such a collision.

Question 2

Case 1: An electron is released from rest in a uniform electric field. Case 2: A proton is released from rest in a uniform electric field of the same magnitude as in case 1 . How does the electric potential energy of the charge-field system behave in these cases?
 a. In case 1 the potential energy increases, but in case 2 it decreases.
  b. In both cases, the potential energy increases.
  c. In case 1 the potential energy decreases, but in case 2 it increases.
  d. In both cases, the potential energy decreases.

[nital]

Answer to Question 1

D

Answer to Question 2

D

[kfurse]

Excellent

[bulacsom]

Gracias!