Then max velocity achievable (without taking friction into consideration) will be between
~0.27 m/s to
~0.53 m/s. It's clear that 1" wheels don't really cut it, hence let's go with 2" wheels.
- Circumference = Diameter * pi
- Velocity = Circumference * RPM
To have acceleration of
0.25 m/s2 (to be able to reach
0.5 m/s velocity in
2 seconds) each motor has to be capable of at least
63.5 mN*m torque.
- Force = Mass * Acceleration
- Torque = Radius * Force
You probably don't want to run motors at 100% duty cycle all the time, so to be on a safe side lets say that You want to achieve aforementioned results while running motors at 75% duty cycle. So, max motor RPM has to be at least
~252 RPM and stall torque has to be at least
~85 mN*m.
For what You want, something like
300 RPM 12V 0.39 N*m motor would be more that enough. Of course if plan on using 12V. What voltage are You planning to use?