An object is thrown vertically at a height of #14 m# at #1 m/s#. How long will it take for the object to hit the ground?

1 Answer
Apr 12, 2016

Answer:

#t=1,59 " s"#
#t=1,69 " s"#

Explanation:

#" if object is thrown downward:"#

#v_i=1m/s#
#y=14m#
#g=9,81m/s^2#

#y=v_i*t+1/2*g*t^2#
#14=1*t+1/2*9,81*t^2#

#4,905t^2+t-14=0#

#Delta=sqrt(1^2+4*4,905*14)#

#Delta=sqrt(1+274,68)#

#Delta=sqrt(275,68)#
#Delta=16,60#
#t=(-1+16,60)/(2*4,905)#

#t=(15,60)/(9,81)#
#t=1,59 " s"#
#"if object is thrown upward :"#
#t_u=v_i/g" "t_u=1/(9,81)" "t_u=0,10" s"#
#"elapsed time to reach peak point"#
#h=v_i^2/(2*g)#

#h=1/(2*9,81)" "h=0,05" m"#
#h_t=14+0,05=14,05" meters total height" #

#14,05=1/2*g*t^2" "28,1=9,81*t^2#

#t^2=(28,1)/(9,81)#

#t^2=2,86#

#t=1,69 " s"#