The frequency of a wave is 560 hz. what is it’s period

Acatapult is tested by roman legionnaires. they tabulate the results in a papyrus and 2000 years later the archaeological team reads (distances translated into modern units): range = 0.4 km; angle of launch = π/5 rad; landing height = launch height. what is the initial velocity of launch of the boulders if air resistance is negligible?

Which is not true about oxygen-17 and oxygen-18?

In a voltaic cell, electrons flow from the (positive/negative) to the (positive/negative) terminal.