You serve a volley ball with a mass of 2.1 kg. the ball leaves your hand with a speed of 30 m/s. the ball energy. can you show me how to calculate this too?

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.

Ascientist wants to test ways to reduce pollution in lake . what is the bestway of doing this

What energy transformations occur each time the skateboarder rolls up the ramp?