Say you threw a ball at angle from the horizontal, with no air resistance. The magnitude of the initial velocity was v. As a function of and v, what is the initial horizontal velocity?
(explain answer please)

Which of the following best describes internal energy? a. the difference between the kinetic and potential energies of the particles in a system b. the sum of the kinetic and potential energies of the particles in a system c. the sum of the kinetic and thermal energies of the particles in a system d. the difference between the kinetic and thermal energies of the particles in a system