Adiamond with a mass of 45 g hangs motionless from a chain. what is the upward force of the chain on the diamond?

The upward force of the chain on the diamond would be the tension in the chain, and this tension would have to support the weight of the 45g that hangs from the chain.

mass = 45 g = 45/1000 kg = 0.045kg

Weight = mg = 0.045 * 10 ≈ 0.45N,            g ≈ 10 m/s²

So the upward force is ≈ 0.45N. 

Gravity bc it’s gravity