Question

An object is projected upward with an initial velocity of 98 m/s it wil strike the ground in ??

Answer 1

To calculate the time of the object remaining in air there is an equation i.e.- T=2u/G 
Where G=9.8 m/s^2=the acceleration of gravity on the object 

so by the equation 

(2*98)/(9.8)
=20 seconds