Keep in mind that forces should be applied over a duration of time. If you’re applying a force for a single frame you will likely not get the intended effect (in this case you’d be better off using an impulse).
Momentum = mass * velocity
change in momentum = force * time
Since mass is constant, change in velocity = force * time.
As you can see if time is very small force will need to be very large.
As FrankieV pointed out, it may also be an issue of scale.