Elijah throws a tennis ball vertically upward. the ball returns to the point of release after 3.5 s. what is the speed of the ball as it is released?

T(return)=3.5 s 

h = vt - (1/2)gt^2 

to the point of release or return h=0 
vt - (1/2)gt^2=0 
t(v - gt/2)=0 ==> 
t(release)=0 or v - (1/2)gt(return)=0 ==> 
v = (1/2)gt(return) 
v=9.81*3.5/2 
v=17.17 m/s

Hope i helped! :)

Cin carbonh in hydrogeno in oxygen