engineering
posted by Anonymous .
a particle falling under gravity falls 39m in certain second find time required to cover the next 30 m take g=9.8

V^2 = Vo^2 + 2g*d.
V^2 = 0 + 19.6*39 = 764.4
V = 27.65 m/s.
d = Vo*t + 0.5g*t^2 = 30 m.
27.65t + 4.9t^2 = 30
4.9t^2 + 27.65t  30 = 0
Use Quadratic Formula and get:
Tf = 0.931 s. = Fall time.
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