Question

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?

Answer 1

`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"`