SOLUTION: I've heard that tossing a coin into a fountain will bring me good luck, so I throw a silver dollar up with a velocity of 5m/sec. and it falls into the fountain 1.3 meters below my

Question 338999: I've heard that tossing a coin into a fountain will bring me good luck, so I throw a silver dollar up with a velocity of 5m/sec. and it falls into the fountain 1.3 meters below my hand. How long is the coin in the air?
In this question i just really dont understand how to do quadratic equations when you dont have the acceleration unless its -9.8m/s squared, but really not sure.
Answer by nerdybill(7384) (Show Source): You can put this solution on YOUR website!
I've heard that tossing a coin into a fountain will bring me good luck, so I throw a silver dollar up with a velocity of 5m/sec. and it falls into the fountain 1.3 meters below my hand. How long is the coin in the air?
In this question i just really dont understand how to do quadratic equations when you dont have the acceleration unless its -9.8m/s squared, but really not sure.
.
Yes, gravity is your acceleration.
.
Applying the equation of motion:
h(t) = (1/2)gt + vt + vo
where
h(t) is height
g is gravity
v is initial velocity
t is time
vo is the initial height
.
h(t) = (1/2)(-9.8)t + 5t + 1.3
h(t) = -4.6t + 5t + 1.3
.
set h(t) to zero and solve for t:
0 = -4.6t + 5t + 1.3
applying quadratic formula we get:
t = {-0.217, 1.304}
we can throw out the negative solution leaving:
t = 1.3 seconds
.
Details of quadratic to follow:

Solved by pluggable solver: SOLVE quadratic equation with variable

Quadratic equation (in our case ) has the following solutons:

For these solutions to exist, the discriminant should not be a negative number.

First, we need to compute the discriminant : .

Discriminant d=48.92 is greater than zero. That means that there are two solutions: .

Quadratic expression can be factored:

Again, the answer is: -0.216769932610683, 1.30372645434981. Here's your graph:

RELATED QUESTIONS
I have four numbers: 2, 92, 79, and 71. Without using any number twice, and always using... (answered by mathmate)

i have no idea how to solve this, can someone please help me? a silversmith has two... (answered by Earlsdon,josmiceli)

i throw a ball into the air in a movie theater.Ithrow it up with an initial velocity of... (answered by Greenfinch)

1) Nineteen coins are what�s in this cup. Better believe me �cause that�s what�s up.... (answered by fractalier)

I throw a ball inot the air in a movie theater. I throw it up with an initial velocity of (answered by psbhowmick,Alan3354,stanbon)

You want to throw a ball vertically upwards so that it will go up 50 meters before... (answered by Edwin McCravy)

Tomorrow I have a test on slope intercept form, and solving system of equation. For slope (answered by stanbon)

GOOD MORNING! I REALLY DO NOT KNOW NOTHING ABOUT ALGEBRA OR GEOMETRY. AND I NEED TO PREP... (answered by nerdybill)

My daughter got this word problem for school and it sounds pretty simple to me but I have (answered by consc198,ankor@dixie-net.com)