Why will a change in velocity have a greater affect on KE than a change in mass?

Aproton is shot from the negative disk toward the positive disk. what launch speed must the proton have to just barely reach the positive disk?

The following table lists the speed of sound in various materials. use this table to answer the question. substance speed (m/s) glass 5,200 aluminum 5,100 iron 4,500 copper 3,500 salt water 1,530 fresh water 1,500 mercury 1,400 hydrogen at 0°c 1,284 ethyl alcohol 1,125 helium at 0°c 965 air at 100°c 387 air at 0°c 331 oxygen at 0°c 316 sound will travel the slowest in air glass aluminum water

What is the value of the charge that experiences a force of 2.4 x 10-3 n in an electric field of 6.8 x 10-5n/c?