Posted by AMY on Thursday, July 1, 2010 at 12:09am.
Let H be the initial height.
Let T be the time it takes to fall the full height H.
g/2 T^2 = 4.9 T^2 = H
(g/2)(T-1.7)^2 = 4.9(T-1.7)^2 = H - 20.5
Combine the equations to eliminate H, so you can solve for T. Then calculate H.
4.9T^2 = 4.9(T-1.7)^2 + 20.5
4.9T^2 = 4.9T^2 -16.66 T +14.161 +20.5
16.66T = 34.66
T = 2.08 s
H = 4.9 T^2 = 21.2 m
Find the height from which you would have to drop a ball so that it would have a speed of 6.4 m/s just before it hits the ground.
Related Questions
physics - A certain freely failing object requires 1.70 s to travel the last 39....
physics - A certain freely falling object requires 1.25 s to travel the last 35....
Physics - A certain freely falling object requires 1.50 seconds to travel the ...
physical - Q: a freely falling object requires 1.50s to travel the last 30.0m ...
physics - An object is dropped from a height H above the ground. This free-...
physics - An object is dropped from a height H above the ground. This free-...
physics - A 20 kg object falls from a height of 30 meters. How many joules of ...
physics - A 20 kg object falls from a height of 30 meters. The amount of kinetic...
physics - If an object is dropped from a tall building and hits the ground 3.0 ...
physics - A helicopter 8.70 above the ground and descending at 2.60 drops a ...
For Further Reading
