why does a hot-air ballon rise? a the volume of the air dispalced by the balloon is less than the volume of the balloon. b the weight of the air dispaced by the ballon is less than the volue of the ballon. c the wight of the balloon is less than the weight of the air displced by the balloon.

Aprojectile is launched horizontally 10m above the ground and with an initial velocity of 15 m/s. a) sketch the trajectory using an appropriate coordination system. b) how long for the projectile to reach the ground. c) how far did projectile travel horizontally before striking the ground. d) determine the projectilex & y position at t-1.3s e) determine the magnitude and direction of projectile velocity at t= 1.3s f) determine the magnitude and direction of projectile acceleration at t-1.3s

Avoltaic cell converts chemical energy to

Most short-period comets do not have randomly oriented orbits because