calculate the density of a solid which weighs 15N in air and 12N in water

Answer 1

Buoyancy = 3 N = rho of water * g * V
3 N = 1000 kg/m^3 * 9.81 m.s^2 * V
V = 2.06 *10^-4 m^3

mass = m = 15 N/ 9.81 = 1.53 kg
so
density = (1.53/2.06)*10^4 = 7423 kg/m^3

Answer 2

what force causes every thing on earth to have wieght

Answer 3

1.0 N

Answer 4

2.06 *10^-4 kg/m^3