Question

I need someone to work this out completely and show all the steps using the formula,
H(t)=-16t^2+vt+s.
A juggler is performing an act by juggling several balls. The juggler throws the balls up at an initial height of 3.9 feet with a speed of 14.8 feet per second. If the juggler did not catch a ball, about how long will it take the ball to hit the floor?

Answer 1

H(T) is the height of ball at time t
when ball hits ground tho is 0
s is initial height = 3.9 ft
v = 14.8 ft/s - the initial speed
so we have
0 = 16t^2 + 14.8t + 3.9
solving for t will give you the time you require

Answer 2

thats a quadratic equation
you can solve it using the quadratic formula
- ar you familiar with this?

Answer 3

for the equation
ax^2 + bx + c = 0

x = [-b +- sqrt(b^2-4ac)] / 2a

Answer 4

Wait so you just plug it in and solve for t? Because other people were saying you can do it another way and it took alot less time.

Answer 5

here a = 16, b = 14.8 and c = 3.9

x = [-14.8 +/- sqrt(14.8^2 - 4*16*3.9)\ / 32

hmm - somethins wrong - this won't work out as we have square root of a negative number
r u sure that formula is correct?

Answer 6

oh sorry - its ny mistake the formula is -16t^2 not 16t^2

Answer 7

its 0 = -16t^2 + 14.8t + 3.9
thats same as
16t^2 - 14.8t - 3.9 = 0

can you try and solve this by the method i've shown?

Answer 8

t = 14.8 + sqrt(14.8^2 - 4*16*-3.9) / 32
= (14.8 + 21.65 )/ 32 = 2.28 seconds

theres also negative root which we can ignore

the answer is 2.28 seconds

Answer 9

I am so lost.. I never got taught this correctly I tried to teach myself and that hasn't gotten me very far.

Answer 10

yes - quadratic equations are a tricky when you come across them first time
there must be some video tutorial about them online
try googling quadratic equations

Answer 11

try khan academy

Answer 12

search for 'khan academy algebra' should do it

Answer 13

See
http://www.khanacademy.org/math/algebra/quadtratics/v/introduction-to-the-quadratic-equation