[FuN]goku

Okay, so there was this guy in my math class , asking my teacher a physics problem.

He wanted to know how long it would take an object to hit the ground, assuming it was from.. say... 10 meters , and had a weight. Our teacher said he didn't know since he hadn't done any physics for a while, so... I kinda got interested in it. (mostly because it will shut my classmate up if it gets answered, and I wont have to listen to him bugging about it )

I don't actually take physics at school, (yet), although I had an introductory course on it(just basics, but i have taken chemistry, and am trying to learn calculus on my own since my school wont let me take it hehe), so pardon any of my ignorance in advance.

I found this formula

d = Vi * t + (0.5)at^2

and from what I understood,

d = distance (m)

Vi = initial velocity (m/s)

t = time in seconds

a = acceleration (m/s^2) , which I also understood to always be 9.8 on earth.

Just as a note, I was using this http://www.physics247.com/physics-homework-help/free-fall.php which is where i got the formula from.

So, I decided, i would try to work out a problem mathematically, and then actually test it by dropping an object.

I measured a meter and dropped a pen from 1 Meter off the ground, and timed it, and did several trials, and got an average of 0.5s

So heres what i got when i worked it out.

1 = (0)t + (0.5)(9.t^2

1 = 4.9t^2

0 = 4.9^2 - 1

At this point, i take what i have and solve using quadratic formula. ( But from what i read, theres another method you can use by just flipping the values to a negative, and moving it over.., which i'm assuming is the same thing, but involves less steps)

t = sqrt(-4(-1)(4.9)) / 2(4.9)

t = sqrt(19.6) / 9.8

t = 4.427 / 9.8

t = 0.451 s

So, i'm just wondering a few things,

1)Did I calculate that correctly?

2)Is mass a factor at all in this equation?

3)Is air resistance a factor at all in the equation?

4)If mass and air resistance are both factors, how would i work them into the equation, and how would i calculate the air resistance?

5)Also, is the area of an object a factor, i.e, a piece of unfolded paper, as opposed to a crumpled piece of paper. (Actually wouldn't that have to do with air resistance?)

Thanks in advance, also, sorry if anything i wrote is unclear, it's 3:10 am, and i'm kinda rusty on ANY physics knowledge i actually do have , but i'd like to brush up on that knowledge since i'm taking 2 physics course next year, and it'd be nice to have a bit of understanding going into the course.

He wanted to know how long it would take an object to hit the ground, assuming it was from.. say... 10 meters , and had a weight. Our teacher said he didn't know since he hadn't done any physics for a while, so... I kinda got interested in it. (mostly because it will shut my classmate up if it gets answered, and I wont have to listen to him bugging about it )

I don't actually take physics at school, (yet), although I had an introductory course on it(just basics, but i have taken chemistry, and am trying to learn calculus on my own since my school wont let me take it hehe), so pardon any of my ignorance in advance.

I found this formula

d = Vi * t + (0.5)at^2

and from what I understood,

d = distance (m)

Vi = initial velocity (m/s)

t = time in seconds

a = acceleration (m/s^2) , which I also understood to always be 9.8 on earth.

Just as a note, I was using this http://www.physics247.com/physics-homework-help/free-fall.php which is where i got the formula from.

So, I decided, i would try to work out a problem mathematically, and then actually test it by dropping an object.

I measured a meter and dropped a pen from 1 Meter off the ground, and timed it, and did several trials, and got an average of 0.5s

So heres what i got when i worked it out.

1 = (0)t + (0.5)(9.t^2

1 = 4.9t^2

0 = 4.9^2 - 1

At this point, i take what i have and solve using quadratic formula. ( But from what i read, theres another method you can use by just flipping the values to a negative, and moving it over.., which i'm assuming is the same thing, but involves less steps)

t = sqrt(-4(-1)(4.9)) / 2(4.9)

t = sqrt(19.6) / 9.8

t = 4.427 / 9.8

t = 0.451 s

So, i'm just wondering a few things,

1)Did I calculate that correctly?

2)Is mass a factor at all in this equation?

3)Is air resistance a factor at all in the equation?

4)If mass and air resistance are both factors, how would i work them into the equation, and how would i calculate the air resistance?

5)Also, is the area of an object a factor, i.e, a piece of unfolded paper, as opposed to a crumpled piece of paper. (Actually wouldn't that have to do with air resistance?)

Thanks in advance, also, sorry if anything i wrote is unclear, it's 3:10 am, and i'm kinda rusty on ANY physics knowledge i actually do have , but i'd like to brush up on that knowledge since i'm taking 2 physics course next year, and it'd be nice to have a bit of understanding going into the course.