Question

a body of mass 5 kg initially at rest is subjected to a force of 20 n what is ke acrequired at the end of 10 s

Answer 1

F = m X a 
a = 20/5
a = 4m/s²

s = ut + 1/2 at²
s = 0 + 1/2 X 4 X 10²
s = 2 X 100
s = 200m

K.E = F X S
K.E = 20 X 200
K.E = 4000J


                                           Hope it helps...................

Answer 2

use ,
F = ma
20 = 5a
a = 4 m/s²
v = u + at
= 0 + 4×10= 40 m/s

now,
kinetic energy = 1/2mv² = 1/2× 5 ×1600 =800× 5 = 4000 jule