A50 kg skater twirls at 0.77 rev/s with her arms extended. she then brings her arms in and twirls at 1.03 rev/s. the skater's mass moment of inertia can be determined by approximating her to be a uniform cylinder with radius 13 cm when her arms are in.

Three charge are arranged as shown in the diagram. the magnitude of the net electrical force acting on the +6 uc charge, rounded to the tenths place, is .

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.

In a heat engine if 1000 j of heat enters the system the piston does 500 j of work, what is the final internal energy of the system if the initial energy was 2000 j? 1. write the equation 2.list out your known variables 3.plug the numbers into the equations 4.solve 5.write your solution statement that includes initial energy and final