Question

Hi Everyone, now I don't necessarily want the answer to this, but a step-by-step understanding on how to solve a question like this. It would greatly help me complete my work. Thankyou

Hideki throws a baseball ball upward with an initial velocity of 12 meters/sec. When he throws the ball, it is two meters above the ground. How long will it take the ball to hit the ground?

1. –16t2+ 12t + 2 = 0
2. –4.9t2 + 12t + 2 = 0
3. –4.9t2 + 12t = 2
4. 4.9t2 + 12t + 2 = 0

Answer 1

Hello and Welcome to OpenStudy! :)

I'll see if I can help, but I am not all that familiar with the topic myself...
hmmm
there was an equation that my physics teacher just told me to remember
which was 0.5at^2 + vt - x = 0
where a = acceleration (or gravitational acceleration)
t = time v = initial velocity and x = height

Answer 2

since gravity only pulls downward (for this given situation) then 'a' is negative

notice that the velocity is given in meters, which effects 16 or 4.9

and the initial height is not -x

Answer 3

The standard equation of motion in a situation such as this one is\[s=s _{0}+v _{0}t+\frac{ 1 }{ 2 }at^2\] ... where \[v _{0}: initial~velocity\]

\[s _{0}=initial~position\]
and
a=acceleration.

Answer 4

In discussing vertical motion where the only acceleration is due to gravity,\[a=-32\frac{ ft }{ \sec^2 }\]

Answer 5

In this case, the initial vertical height is 2 meters.

The initial vertical velocity is 12 m/sec.

Please do your best to put all this info together, and then to decide which of the four given possible answers is the correct one.