Question

a football is thrown vertically upward in air if air resistance is taken into consideration and t1 and t2 are timetaken by it in upward motion and downward motion respectively is​

Answer 1

we know, air resistance or air drag always opposes the motion of body.

so, if football moves upward with speed u, air resistance, a is acting downward on football.

then net acceleration acting on football = (g + a), downward.

now time taken by football to reach destination point, t1 = u/(g + a) .....(1)

if football moves downward from same height, air resistance, a is acting upward on football.

then net acceleration acting on football = (g - a) [ downward]

now time taken by football to reach the ground, t2 = u/(g - a) .....(2)

from equations (1) and (2),

we get, t1 < t2