a meteorite slams into the earths crust and penetrates d=(1200t-36000t^2)m in t seconds after impact. What is the maximum depth of penetration?

Answer 1

dd/dt = 1200 - 72000t
= 0 for a max
72000t = 1200
t = 1/60

d = 1200(1/60) - 36000(1/3600)
= 10 m

Answer 2

Thanks Alot I was really puzzled on this one.