Why do the planets orbit the Sun?

To understand why the planets move in orbits we need to understand a bit more about gravity. Remember https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315193892/2143c097-43f6-474f-b507-c12feffdfd35/content/pg182_1.tif"/>