Hey guys...please help me with both b) and c) in this question.

Which statement correctly describes a step-up transformer? a. it increases the amount of electric energy available. b. it increases the voltage of an electric current. c. it changes direct current into alternating current. d. it has more loops of wire in its primary coil.

Which changes would result in a decrease in the gravitational force btween two objects? check all that apply

Aball is thrown vertically upwards from the top of a tower with a speed of 100m/s.it strikes the pound near the base of the tower after 25sec . the height of the tower is