physics
posted by bob .
two objects are thrown from the top edge of a cliff with a speed of 10 m/s. one object is thrown straight down and the other straight up. if the first object hits the ground in 4.0 second, the second hits the ground in ________ seconds after the first object.

physics 
MathMate
Assume no air resistance.
For the object thrown downwards,
t=4 s
vi=10 (+ve upwards)
g=9.8 m/s²
S=vi*t+(1/2)gt²
=10*4+(1/2)(9.8)(4²)
=118.4 m
For the object thrown downwards,
t=unknown
vi=+10 (+ve upwards)
g=9.8 m/s²
S=vi*t+(1/2)gt²
118.4=+10*t+(1/2)(9.8)(t²) ...(1)
Solving the quadratic equation (1), we get
t=4 or t=296/49
Can you take it from here? 
physics 
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physics 
phill
12
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