Alright in my class we are learning about free fall and crap.

I've wasted tons of time on thins one problem and it's now past midnight and I still haven't gotten it yet.

ok

Maria throws an apple vertically upward from a height of 1.3m with an initial velocity of +2.4m/s

If the apple is not caught, how long will the apple be in the air before it hits the ground?

Please show all of the steps you did because I got a completly wrong answer. The back of my book says that it's .82s

God Help...

Also in our textbook free fall is

-9.81 m/s^2

if it is crap, and you are wasting your time, get out of the class, you have better things to do, like....

1) Go to the college bookstore, or BarnesNoble, and take a look at Schaums College Outline Series, College Physics. It will help you. And it is inexpensive.

2) the equation of motion is...

finalposition=intialposition+ vi*time + 1/2 g time^2
the final postition is zero, the initial postion is 1.3m .
g is -9.81m/s^2; vi is 2.4m/s
solve for time

0=1.3+2.4t - 4.9t^2

Use the quadratic equation.

I understand your frustration. I can explain the steps to solve this problem and help you obtain the correct answer.

To solve this problem, we can use the equation of motion for free fall:

h = ut + (1/2)gt^2

Where:
h = height
u = initial velocity
g = acceleration due to gravity (approximately 9.8 m/s^2)
t = time

In this case, the initial height, h, is 1.3 m, and the initial velocity, u, is +2.4 m/s. We need to find the time it takes for the apple to hit the ground, so we can set h equal to 0.

0 = 1.3 + 2.4t - (1/2)(9.8)t^2

Let's simplify and solve for t:

-(4.9)t^2 + 2.4t + 1.3 = 0

To solve this quadratic equation, we can use the quadratic formula:

t = (-b ± sqrt(b^2 - 4ac)) / 2a

For our equation, a = -4.9, b = 2.4, and c = 1.3. Let's substitute these values into the formula:

t = (-2.4 ± sqrt((2.4)^2 - 4(-4.9)(1.3))) / (2(-4.9))

Now, let's calculate the discriminant (the term within the square root):

D = (2.4)^2 - 4(-4.9)(1.3)

D = 5.76 + 101.44

D = 107.20

Since D is positive, we can proceed with the calculation:

t = (-2.4 ± sqrt(107.20)) / (-9.8)

Now, let's simplify and calculate both possible values for t:

t = (-2.4 + sqrt(107.20)) / (-9.8) ≈ 0.82 s

t = (-2.4 - sqrt(107.20)) / (-9.8) ≈ -0.19 s (This value is not physically meaningful because time cannot be negative in this context.)

Therefore, the correct answer is approximately 0.82 seconds.

Please note that in the real world, there are other factors to consider, like air resistance, which can affect the actual time it takes for an object to fall. However, for this problem, we assume a vacuum and neglect air resistance.