Mass Spectrometry Calculation HelpWatch
v = d/t, so for the second question, substitute (d/t) into v^2 so that you get the equation KE = md^2 / 2t^2, then rearrange the equation to make t the subject. for the third, do the same but make d the subject.
bear in mind that the mass to use in the KE equations is Mr / L; Mr is the molar mass given and L is avogadro’s constant. this’ll give you the mass in grams, so convert to kg if the question asks you to.