An antiaircraft shell is fired vertically upward with a muzzle velocity of 1000 m/s. Calculate: (a) The maximum height it can attain. (b) The time taken to reach this height. (c) The instantaneous velocities at the ends of 20 secs and 50 secs.​

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