A resultant force of 20 N has accelerated a body of mass 4.0 kg from rest, until the present moment, at which time its kinetic energy is 1800 J. If this force continues to act unchanged, how much extra kinetic energy will the body gain during the next 2 seconds?

Answer:

27) E

KE = ½mv² = 1800 J
v = 30 m/s

F = ma
a = F/m = 20/4 = 5 m/s²

v = u + at

v = ?
u = 30
a = 5
t = 2