Two blocks are placed at the ends of a horizontal massless board, as in the drawing. the board is kept from rotating and rests on a support that serves as an axis of rotation. the block on the right has a mass of 4.8 kg. determine the magnitude of the angular acceleration when the system is allowed to rotate.

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.