If the pendulum has 15 J of gravitational potential energy and it is at rest, how much mechanical energy does the pendulum have?

Jessica is traveling from miami, florida, to chicago, illinois. using the map, tell one way the land will change during the second half of her trip.

Achemist 16 drop copper metal from copper chloride solution. the chemist place is 0.50 g of aluminum foil in a solution containing 0.75 g of copper (ii) chloride. a single replacement reaction takes place. which statement explains the maximum amount of copper that the chemist can extract using this reaction?

Can someone me with 3 and 4 plz. this is for masteries test.