Jeff is part of a trekking team. as he climbs a hill, he drops his water bottle, which has a mass of 0.25 kilograms. the bottle slides down the hill and is moving at a velocity of 14 meters/second the instant it hits the ground. the vertical height from where jeff dropped the bottle is meters. ignore friction, and use , pe = m × g × h, and g = 9.8 m/s2.

During physical science, ms. greene challenged her students to produce an energy transformation. james and jill wrapped a 4-inch nail with a coil of fifty turns of wire. they connected one end of the coil to one terminal of a knife switch. they connected the other terminal of the knife switch to the battery. finally, they connected the end of the coil to the other terminal of the battery. james held the tip of a 1-inch nail near the flat end of the 4-inch nail. jill closed the knife switch quickly and then opened it. the 1-inch nail was pulled toward the 4-inch nail. what is the best explanation of why the nail moved? a) electrical energy was converted to mechanical energy in the 1-inch nail. b) the 4-inch nail became an electromagnet and the magnetic force attracted the 1-inch nail. c) the electric current in the 4-inch nail was converted to mechanical energy in the 1-inch nail. d) the 4-inch nail had a positive charge and the 1-inch nail had a negative charge. opposites attracted.

Which type of bond is found between the atoms of a molecule? a. metallic b. delocalized electron c. covalent d. ionic

Hydrogen and helium are both members of?