Motor sizing

As we need mass of our bot to calculate the F, so the mass of the bot is 1.5kg

F=mg

m= Mass of the bot in kg

g= Acceleration due to gravity

F= 1.5*9.8

F= 14.7N

T= F*R

Here r=2cm

T= 14.7*2

T=29.4

Hence we are using 60 R.P.M DC motor

Battery sizing

As we required 12v volts we are directly connecting to 12v adaptor