A body is thrown vertically upwards, remaining 4s in the air. Calculate the maximum height that the body reaches.

20 m

Explanation:

Given:

v = 0 m/s

a = -10 m/s²

t = 4 s / 2 = 2 s

Find: Δy

Δy = vt − ½ at²

Δy = (0 m/s) (2 s) − ½ (-10 m/s²) (2 s)²

Δy = 20 m

i am pretty sure it is c because when people are closer together, they cannot move as freely. picture being in a mostly full elevator, for instance. the people are right next to you, and you can barely move.