Displacement = 31 - 16 = +15 m
It is a very reactive metal with 11 protons ,12 neutrons, 11 electrons, and 1 valence electron
Classify is not a step in the inquiry process
To solve this problem we will apply the energy conservation theorem for which the work applied on a body must be equivalent to the kinetic energy of this (or vice versa) therefore


Here,
m = mass
= Velocity (Final and initial)
First case) When the particle goes from 10m/s to 20m/s



Second case) When the particle goes from 20m/s to 30m/s



As the mass of the particle is the same, we conclude that more energy is required in the second case than in the first, therefore the correct answer is A.