Question

a 5kg mass is dropped from a height of 30m above the ground. determine the velocity of the mass when it is 18m above the ground.

Answer 1

Google Galileo and leaning tower of Pisa
Mass is irrelevant if air resistance is ignored

a = -g = -9.81 m/s^2
h = Hi + Vi t + (1/2) a t^2
18 = 30 + 0 t - 4.9 t^2
- 12 = -4.9 t^2
t = 1.56 seconds falling
v = Vi + a t
v = 0 - 9.81 (1.56)
v = - 15.4 m/s

Answer 2

thanks