Question

A constant force acting on a body of mass 3kg changes its speed from 2m/s to 3.5m/s in 25sec.The direction of motion of the body remains unchanged.what is the magnitude and direction of the force?

Answer 1

a=v-u/t
3-2.5/25=3/50
f=ma
3*3/50=9/50N
(not sure about the answer though)

Answer 2

ans is 0.18 N
As, F=ma
a=(v-u)/t
                        v=3.5m/s
                        u=2m/s
                        t=25sec
a =(3.5-2)/25      m/s^-2
a= 0.06 m/s*s
m=2 kg
F=ma
F=2Kg*0.06 m/s*s
F=0.18 Kg*m/s*s = 0.18 N