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tehmatriks
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Homework Statement
A stone is projected vertically upwards from the ground with an initial velocity of 80 m s-1. Find the greatest height reached and the time taken. When will the stone be 96 m above the ground?
Homework Equations
[v = u + at], [s = ut + ½at2], [v2 = u2 + 2as]
assume all falling objects have an acceleration of 9.8 m s-2 vertically downwards.
The Attempt at a Solution
accerleration "a" = -9.8 m s-2
initial velocity "u" = 80 m s-1
final velocity "v" = 0 m s-1
time "t" = ? s
finding time "t" using
v = u + at
0 = 80 + (-9.8)t
t = 80/9.8
t = 8.16 s
finding greatest height i.e distance "s" using
v2 = u2 + 2as
02 = 802 + 2(-9.8)s
s = 802/2(9.8)
s = 326.53
Now for the second bit, finding when the stone will be 96 m above the ground.