Please please help. I don’t understand this.

What is the weight of a 8-kg substance in n, kn, kg·m/s2, kgf, lbm·ft/s2, and lbf?

During the experiment if you could triple the breakaway magnetic force with all other quantities left unchanged, what is the new value for the critical velocity if it was v0 (initial velocity), initially? (b) now if you halved the radius with all other quantities left unchanged, what is the new critical velocity if it was v0 (initial velocity), initially? (c) if during the experiment, critical velocity quadrupled with all other quantities left unchanged, what is the new breakaway force if its magnitude was initially f0,?

An electron in an x-ray machine is accelerated through a potential difference of 1.00 × 104 v before it hits the target. what is the kinetic energy of the electron in electron volts?