Question

A block has a volume of 0.07 m3 and a density of 3,500 kg/m3. What's the force of gravity acting on the block (and weight) in the air?

A. 1,715 N B. 686 N C. 2,058 N D. 2,401 N

Answer 1

The force of gravity is simply the mass times the gravitational acceleration, which I suppose is 9.8 m/s^2 in your exercice.
The mass can be obtained from d=m/v, where
d= density,
m=mass
v=volume.
m=3500*0.07=245 kg.
Therefore force of gravity (which is the weight) is F=m*g=245*9.8=2401 N.