Calculate the potential energy of a 20 kg object at rest on a ledge 30 meters above the ground. O 600 J
O 6.5 J
O 50 J
O 9000 J
5886 J

Students design a model roller-coaster track. they place a rubber ball at the highest point on the track and let it go. the ball rolls along the track pulled only by the force of gravity. eventually, it comes to a stop. which change to the design will result in the ball moving the greatest distance?

What was the first instrument to ever record an earthquake?

Which of the following is not a physical property of mattera. melting pointb.heat of combustionc. viscosityd. boiling point