a vending machine ate another students dollar. the student had enough. he dropped the vending machine off a 20 m cliff. at the same time his buddy at the bottom of the cliff throws a grenade straight up towards the vending machine. the grenade strikes the vending machine after .3 seconds. how far up the cliff does the grenade impact the vending machine?

H = ho -(Vo*t + 0.5g*t^2.

H = 20 - (0 + 4.9*(0.3)^2) = 19.56 m. =
Ht. of V. machine above Gnd = Ht. of grenade above Gnd.