newton meters is the unit of torque, and at 100 newtons of acceleration that is 1.25m/s/s of acceleration, which in my opinion is more than just cruising
(Newtons = Mass{Kg} * Acceleration{Meters per second per second})
(Torque = Newtons * meters)
to make it a bit easier to process, 100N of acceleration would be accelerating by 5Km/h every second,
(m/s * 3.6 = Km/h)
and now for your gearing, you will have some issues there, as RPM gets scales along with torque, so at a gearing of 10:1 with your wheel whizzing along at 700RPM, would require your motor to be running at 7000RPM, tad high....
lets assume a more practical 3:1, as most motors happily run into the 2-3000 range, this is where that torque equation once again matters, to get 100N to a point 0.06m (radius) from the axel of the wheel, requires 6N/m of torque, if direct driven, (newtons * meters)
hmm, looks like you wouldnt really even need the gearing, , ((KW = torque * 2 * pi* wheel rpm)/60000),
as that comes fairly nice value of 500W, (440W actually) and this value scales linearly with your acceleration so if you want to use a 200W motor instead, thats only 0.5m/s/s or 1.8Km/h/s
but just to make it convinient for you, no matter what your gearing ratio the effective power must remain the same, only the torque required of the motor is lowered, so 3:1 would only require 2N/m of force and the motor would spin along at 2100RPM
note that this is assuming power at the rotor of the motor, not power fed into it, as no motor is 100% efficient,