The question doesn't tell us WHERE the m³ of water is. It makes a big difference, so I'll go out on a limb and assume that it's on the Earth.
Mass of the water . . . 10³ kg
Mass of the sun . . . 1.989 x 10³⁰ kg
Distance between the sun and the water . . . 1.496 x 10¹¹ meters
Newton's gravitational constant 'G' . . . 6.674 x 10⁻¹¹ m³/kg-s²
Formula for the force of gravity:
Force = G·(one mass)·(the other mass) / (distance between them)²
Force = (6.674 x 10⁻¹¹ m³/kg-s²)·(10³ kg)·(1.989 x 10³⁰ kg) / (1.496 x 10¹¹ meters)²
Force = (6.674 x 1.989) / (1.496)² · (10⁻¹¹ ⁺³ ⁺³⁰ ⁻²²) · (m³ · kg · kg) / (kg · s² · m²)
Force = (5.931) · (10⁰) · (m·kg/s²)
Force = 5.931 Newtons
I've never done this calculation before. It's pretty cool. It turns out that if there's something on the ground in front of you that weighs around a ton, then there's about 1.3 pounds of gravitational force pulling it toward the sun !
