The function y = 16t^2 + 486 models the height y in feet of a stone t seconds after it is dropped from the edge of a vertical cliff. How long will it take the stone to hit the ground? Round to the nearest hundredth of a second.
A. 7.79 seconds
B. 11.02 seconds
C. 0.25 seconds
D. 5.51 seconds

Question

The function y = 16t^2 + 486  models the height y in feet of a stone t seconds after it is dropped from the edge of a vertical cliff. How long will it take the stone to hit the ground? Round to the nearest hundredth of a second.
	A. 7.79 seconds 	
	B. 11.02 seconds 	
	C. 0.25 seconds 	
	D. 5.51 seconds

dariyana · Answer

what do youthink it is

anonymous · Answer

I have no clue

dariyana · Answer

ok

campbell_st · Answer

just a quick question are you sure the equation is correct..?

anonymous · Answer

Yup!

campbell_st · Answer

no negatives... with 16t^2..?   e.g. - 16t^2

hartnn · Answer

hit the ground means y=0...so now u solve the quadratic equation....easy one

hartnn · Answer

ya -ve sign should be there somewhere

campbell_st · Answer

its not that easy as you will have a complex solution

hartnn · Answer

assuming negative sign is there root(486/16) will give 5.51...