Isotope a contains 56 protons and 80 neutrons. isotope b contains 55 protons and 81 neutrons. isotope c contains 57 protons and 80 neutrons. isotope d contains 56 protons and 74 neutrons. which isotopes have the same mass number?

mass number is defined as sum of number of protons and neutrons

so here for Isotope A

Isotope A contains 56 protons and 80 neutrons.

Mass number will be given as

For Isotope B

Isotope B contains 55 protons and 81 neutrons.

For Isotope C

Isotope C contains 57 protons and 80 neutrons.

For Isotope D

Isotope D contains 56 protons and 74 neutrons.

So here Isotope A and Isotope B has same mass number

we're given that v₀ = 0 and a = 5.4 m/s². therefore, since v = at + v₀ for constant acceleration the equation for velocity is

after 28s,

m/s

which i would round to 150 m/s as my final answer