Question

An object allowed to fall from height of 70m at the same time a projectile is fired straight up at velocity of 35m/s. When and where will they pass each other?

Answer 1

$$Y=70- (g\times t^2)/2$$

is the equation of motion of the object

$$Y=35\times t-(g \times t^2)/2$$

is the equation of motion of the projectile

Equate these equations:

$$70- (g\times t^2)/2 =35\times t-(g \times t^2)/2$$

From here: t=2sec; Y=50 meter