Hi,did anyone know how to convert 1.80 Mg/m3 to Kn/m3 ?please!help!

Mg=mega gram Kn=kilonewton m3=meter3

You are asking how to convert a mass per unit volume to a force per unit volume. If this is correct, you have to assume a value for g, say 9.81m/s^2 (same as 9.81N/kg), so this conversion would be correct for the earth but not on the moon!

The symbol for newton (spelled in full with a small 'n')is a capital 'N'.
The symbol for kilo is a small 'k'. (capital K is kelvin).

There are 1000kg in 1 Mg, so 1.8Mg = 1800kg
Weight of 1800kg = mg = 1800 x 9.81 = 17658N = 17.7kN (to 3 significant figures)

So the answer is 17.7kN/m^3

Since both units are divided by m³
just convert 1.80E3 Kg to E3 N by multiplying by 9.81 N/kg
(9.81)(1.80) = 17.7
ANS = 17.7E3 kilo-newton/m³

F =m *a
F = 1.800.000gram * 9.81 (gravitational acceleration of the earth)
F = 17.658.000N
F= 17658 kN