If you were in a spaceship and fired a cannonball into frictionless space, how much force would have to be exerted on the ball to keep moving once it has left the spaceship?

Arunner is training for an upcoming marathon by running around a 100-m-diameter circular track at constant speed. let a coordinate system have its origin at the center of the circle with the x-axis pointing east and the y-axis north. the runner starts at (x, y) = (50 m, 0 m) and runs 2.5 times around the track in a clockwise direction.