This is because in J.J. Thompson model, there would be no nucleus to reflect the alpha particles. This means there would be no reflection of the particles, making the answer A
The correct option is A. J.J Thompson proposed the plum model of atomic structure. The model states that the atom is a sphere of positively charged matter in which electrons are embedded. Rutherford designed an experiment to verify the truth of this model. He set up a beam of alpha particles which are to be passed a thin gold foil. If the JJ model of atomic structure is correct, all of the alpha particles suppose to pass through the foil, but some of the alpha particles bounced back while those that passed through the foil emerged at different angles.
This question can be answered by using conversation of energy.
Explanation:
Note that we take because we are looking for the minimum initial speed for the penguin to reach the top of the second hill. Any other speed more than this will already be enough for him.