Q1. On an open field, a cannonball launches at the angle of 50° with respect to the ground. Some moment later, you observe that the cannonball is still in flight and on its way up. What can you affirm about the cannonball's velocity at that instant of time as compared to its initial velocity (at launch)? vx and vy stand for the x and y components of the cannonball's velocity, correspondingly (with x pointing parallel to the ground and y pointing up, as usual). Choose the best answer and give a short explanation for your choice.
a. Both vx and vy have not changed.
b. Both vx and vy have increased.
c. vx has decreased and vy has increased.
d. vx has not changed and vy has decreased.
e. vx has increased and vy has not changed.
f. vx has increased and vy has decreased.
Q2. Work out the buoyant force due to the surrounding air on a man weighing 800 {rm N}. Imagine his average density is the same as that of water, and surrounding air temperature is 0 rm ^circ C.