Why is the moon the primary cause of earth’s tides?

The moon's gravitational pull on the earth is strong enough to tug the oceans into bulge. If no other forces were at play, shores would experience one high tide a day as the earth rotated on its axis and coasts ran into the oceans' bulge facing the moon 

Because of the gravitational force of the moon on the tides of the ocean

half way is 0.5

N 7.5 N