The pony express was a popular method of moving the mail quickly in the mid-1800s. suppose a pony's momentum is calculated to bethe mass of the pony is 450 kg. what is the magnitude of the pony's velocity? a. 16 km/hrb) 320 km/hrc) 630 km/hrd) 160 km/hr

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