Free falling object in physics.?

While sitting on a tree branch 12.0 m above the ground, you drop a chestnut. When the chestnut has fallen 2.8 m, you throw a second chestnut straight down. What initial speed must you give the second chestnut if they are both to reach the ground at the same time?

Free falling object in physics.?
First chestnut is in freefall. The initial velocity, if i am reading it right, is 0. So the total distance fallen is 12 m....and we get 12=(1/2)gt^2=4.9t^2...solve for t.



Then do the same thing for 2.8 instead of 12 and subtract the two times. This will give the total time for the second chestnut.



That one is thrown, so it has initial velocity (which you need to find). Distance is 12, so we get:



12=V0(t)+(1/2)gt^2



You have t and g is just acceleration due to gravity (9.8), so you can solve for V0.
Reply:Try the Isaac Newton method and drop two lead balloons two seconds apart. The first lead balloon to hit dirt fails to explode. The second lead balloon explodes by hitting the first lead balloon, causing both lead balloons to explode silmultaniously. The sound of the explosion[s] travels around the earth at about 760mph - when the sound returns from the other extension, the time gap is measured. This then gives an inaccurate English measurement in inches per mile per second and thus equals the weight times speed over the distance travelled at a given time on a slightly damp day.



LESSON No.1.

Measuring gravity with the last of the great alchemists, Sir Isaac Newton.



Sir Isaac Newton thought about gravity and the apple. He thought that maybe gravity was not just limited to the earth and the objects on it. ...

http://inventors.about.com/library/inven...
Reply:wrk out the time taken ........... by the time the 1st chesnut reaches......2.8 m

n then wrk out the whole time .,........ in which it falls to the ground



1st chesnut



s= ut+ 0.5 at^2

u=0

s= 12

a= 9.8



n then the diffrnce in time betwn those 2 times is the time it takes for the 2nd chesnut to reach the ground



n then

u knw wat the time is for the second chesnut

so sub in time in the same formula

to get u



hope tht it helps



tk cr m8
Reply:jeez, i dont know, the last time i did that stuff was ages ago.

sorry i cant help.
Reply:64ft/sec to catch it up as an object falls at 32 ft /per sec.

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