A body of mass 20kg initially at rest is subjected to a force of 40N for 1second calculate the change in kinetic energy

AAAaannndd the bot gets it wrong yet again!

KE = 1/2 mv^2
v = at
F = ma
KE = (1/2) × 20kg × (40N/20kg * 1s)^2 = 1/2 * 20 * 4 = 40J

Change in kinetic energy = (1/2) × 20kg × (40N)2/1s2 = 3200J