The space shuttle needs to slow down in order to return from its orbit. It does so by reversing direction and firing its 3 main engines for a short amount of time. The mass of the space shuttle is 2.0 x 106 kg and has an orbital speed of 8000 m/s. The combined force of the 3 engines is 1.8 megaNewtons. How long of a burn is needed to reduce the orbital speed by 10%.