1 pixel = 1cm
1 impulse = 1/100 n/s
1 mass = 10g

100 impulse: 1 n/s
100 mass: 1 kg

cm/s to km/h = * 0.036

m/s * kg*100 * 100 = get speed at m/s
e.g 
4.638889 * 781 * 100 * 100
781(mass of elise)

impulse in godot is n/s used in 1 second