2. atoms of an element that have the same number of protons and a different number of neutrons
Explanation:
Isotopes of an element is made up of atoms of an element that have the same number of protons and a different number of neutrons.
The number of protons are the positively charged particles in an atom
The number of neutrons are the uncharged particles.
Isotopy is the existence of two or more atoms of the same element having the same atomic number but different mass numbers due to the differences in the number of neutrons in their carious nuclei.
Isotopes have have the same electronic configuration and hence will have similar chemical properties. They only differ in their masses.
We must solve this problem by defining that when we have a constant velocity, the acceleration is equal to zero. That is, when there is no speed change, there is no acceleration. We can understand it very easily by means of the following equation of kinematics.
where:
Vf = final velocity = 55 [km/h]
Vo = initial velocity = 55 [km/h]
a = acceleration [m/s²]
t = time [s]
As we can see there is no change in speed, and the difference between the two is equal to zero.