Question

a cup falls off of a table from a height of .3m. what is the impact speed of the cup

Answer 1

You have : 
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vf^2 - v0^2 = ( 2 ) ( -g ) ( yf - y0 ) 

vf^2 = vo^2 + ( 2 ) ( -g ) ( - 0.3 m ) 

vf^2 = ( 0.0 m/s )^2 + ( 2 ) ( - 9.807 m/s^2 ) (- 0.3 m ) 

vf^2 = 5.884 m^2 / s^2 

vf = ( 5.884 m^2 / s^2 )^1/2 

vf = - 2.43 m/s <-------------- [ minus sign since moving downward ]