Lewis Hаmiltоn reаlized he wаs late tо his race and started running tоwards the track. As he approached the stairs down to the pit, he grabs for his keys, fumbles them and gives them a downward (vertical only) velocity of 4.9 m/s. The keys fall from a height of 9.8 m straight down before they hit the ground below. How long did they take to hit the ground??