A person skateboarding is part of a closed system that has 1,450 J of mechanical energy. If the kinetic energy of the person increases from 200 J
to 825 J, what happens to the gravitational potential energy of the system?
O A. It decreases from 1,250 J to 625 J.
B. It decreases from 1,450 J to 1,025 J.
C. It increases from 1,250 J to 2,075 J.
O D. It increases from 625 J to 1,250 J.
I

Ten students stand in a circle and are told to make a transverse wave. what best describes the motion of the students? each student bumps the shoulder of his or her neighbor. at the exact time, all students take a step to the right. the students skip clockwise, going in a circular motion. one at a time, each student lifts his or her hands up and then down.

Agroup of students is studying convection currents. they fill two identical balloons with the same amount of helium. one balloon is placed in a freezer and the other in an area with warm air. after 10 minutes, the balloons are released from a height of 1 meter. which of the following do the students most likely observe? question 2 options: the balloons rise at the same rate. both balloons are the same size. the ballons both rise. the cold ballon is larger than the warm balloon. the cold balloon expands and rises. the warm balloon shrinks and sinks. the warm balloon expands and rises. the cold balloon shrinks and sinks.

Why is the energy that results from a roller coaster's position at the top of a hill referred to as potential energy?