explain how a roller coaster functions using gravity and momentum. Why does it not need an engine or a motor to speed it up and slow it down?

Two pans of a balance are 24.1 cm apart. the fulcrum of the balance has been shifted 1.33 cm away from the center by a dishonest shopkeeper. by what percentage is the true weight of the goods being marked up by the shopkeeper? assume the balance has negligible mass. answer in units of %.

Aflute player hears four beats per second when she compares her note to a 523 hz tuning fork (the note c). she can match the frequency of the tuning fork by pulling out the “tuning join” to lengthen her flute slightly. what was her initial frequency?

Why is a noble gas different from other elements