help please :(

[watchthesky30]

Suppose an object is dropped from a height h0 above the ground. Then its height after t seconds is given by h = -16t ²+h0, when h is measure in feet. Use this information to solve the problem.
A ball is dropped fom the top of a building 96ft tall.
a) how long will it take to fall half the distance to ground level?
i got ?3

b)how long will it take to fall to ground level?

 

[arthur ohlsten]

given:
h=-16t^2+ho
h0=96 ft
find:
t when h=48 ft

h=-16t^2+h0 substitute
48=-16 t^2+96 subtract 48 from each side
0=-16t^2+48 add 16t^2 to each side
16t^2=48 divide both sides by 16
t^2=3 take square root of each side
t=sqrt3 secs answer
Arthur

 

[mmm4444bot]

h = -16t ² + 96

a) how long will it take to fall half the distance to ground level?
i got ?3

b)how long will it take to fall to ground level?

You got t = sqrt(3) by substituting the height 48 feet for h and solving for t, right?

When the object hits the ground, then h = 0 feet, right?

Journey onward!