Tides are created by the gravitational attraction of the sun and moon on Earth.

Need help with physics question. Tides are created by the gravitational attraction of the sun and moon on Earth. Calculate the net force pulling on Earth during a) a new moon, b) a full moon, c) a first quarter moon. The diagram is intended to help your understanding of the situation but is not drawn to scale. (m of the moon = 7.35 x 10^22 kg, m of the earth = 5.98 x 10^24 kg, m of the sun = 1.99 x 10^30 kg, distance from e-m = 3.84 x 10^8 m, d e-s = 1.5 x 10^11 m)