A student uses a lever and fulcrum to lift a rock off the ground. Which option describes when potential energy is converted into kinetic energy during this process?

a. when the lever is wedged beneath the rock but before it has been lifted

b. when the student presses down on one side of the lever to cause it to move

c. when the rock rests on the ground without the lever

d. when the rock rests above the ground

An animal cell loses the ability to convert energy stored in food to energy that the cell can use. which of the cell's organelles has stopped working? a.the mitochondria b.the nucleus c.the vacuoles d.the endoplasmic reticulum

Connect the whole numbers on the periodic table to indicate what they represent?

The table lists the lattice energies of some compounds.compoundlattice energy (kj/mol)lif            –1,036licl            –853naf            –923kf            –821nacl            –786which statement about crystal lattice energy is  best  supported by the information in the table? the lattice energy increases as cations get smaller, as shown by lif and kf.the lattice energy increases as the cations get larger, as shown by lif and licl.the lattice energy decreases as cations get smaller, as shown by nacl and naf.the lattice energy decreases as the cations get smaller, as shown by naf and kf.