Electromagnetic radiation with a frequency of 8.6 x 1014 hz incident on an unknown metal surface causes ejection of photoelectrons with kinetic energies of 1.3 x 10–19 j. what is the unknown metal?

A500g object falls off a cliff and losers 100 j from its gravitational potential energy store. if the gravitational field strength g=9.8n/kg, how high is the cliff?

Heena wants to measure the volume of a ball that is 24 cm across. how should she set up her equation?

On a day when the barometer reads 75.23 cm, a reaction vessel holds 250 ml of ideal gas at 20 celsius. an oil manometer ( ρ= 810 kg/m^3) reads the pressure in the vessel to be 41 cm of oil and below atmospheric pressure. what volume will the gas occupy under s.t.p.?