BGring, lots of ways to do this. My favourite is to stick to kg, m, and s.
Convert your 270kph into 75 m/s, your 5g into 0.005kg and your 27.5cm into 0.275m.
You find the force on the 5g weight is 102.3 N (=102.3 kg m/s^2). What does that mean? Well 1 N (Newton) is about the weight of 1 apple in Earth's gravity (easy way to think of it: Newton..apple), so 102.3N is the same force as 100 apples weigh.
If you want g then you don't want a force, you want the acceleration. It's probably already been discussed in this thread, but to keep the tip weight moving in a circle it's velocity must change (in direction, not necessarily in speed). So the acceleration responsible for changing the tip weight's velocity is just the v squared over r part of the equation.
This works out to 20,454 m/s^2 or about 2085 g's !
Easy to see why balancing is so important.