7. In a distant galaxy a war is being fought, and a large space battleship (mass 10,000,000kg) is defending itself using powerful mass driver cannons. These mass drivers accelerate dense projectiles (mass 5000kg) to very high speed (100,000m/s relative to the battleship) and are used to damage hostile ships. The battleship is traveling at 20,000m/s with its engines off when it fires its mass driver cannon straight ahead 10 times at an approaching ship. What is the speed and direction of travel of the battleship after it has fired all 10 shots?