Question

a force acting on a 20 kg mass change its velocity from 5 m per second 2metre per second calculate the work done by the force

Answer 1

F=ma
a=v/t-u/t
a=2-5
a=-3
m=20kg
D=-60N

Answer 2

Work done = Kinetic energy possessed by the mass

final velocity(v) = 5 m/s

initial velocity(u) = 2m/s

mass(m) = 20 kg

=1/2 m (v* - u*).

=1/2 x 20 x [(5)*-(2)*]

=1/2 x 20 x [25-4]

=1/2 x 20 x 21

=10 x 21

=210 Joule(J)

Please note that * is used in place of whole square