A cart falls from a track with an acceleration of 10 m/s2 (which is always the acceleration due to gravity). If it falls for 9 seconds before hitting the ground, what is it’s velocity at impact? (show work plz)

Which statement is true about an object that is moving in a circular motion due to centripetal force, f, when the radius of its circular motion is doubled? the new force then becomes equal to 2f the new force then becomes equal to f the new force then becomes equal to f/2 the new force then becomes equal to f2 the new force then becomes equal to 1/f