Question

were are doing free fall right now in the class

the question is

A worker drops a wrench form the top of a tower 80.0m tall. What is the velocity when the wrench strikes the ground?

I know that the change of distance 80.0m

I know aceleration of free fall is -9.81m/s^2

but I don't think that I have enough information to find the velocity final because I don't know the velocity initial I'm completly lost

Help Me

Answer 1

Assume that he just dropped the wrench and the initial velocity is 0
-80 = -(1/2) 9.81 t^2
t = sqrt (160/9.81) = 4.04 seconds before crash
so
V = 0 - 9.81 t = -39.6 m/s

Answer 2

Fhghu