An object is thrown verticallly upward and rises to a height of 10m. Calculate (i) the velocity with which the object was thrown upwards and (ii) the time taken by the object to reach the highest point.

Explanation

Distance travelled s=10m
Final velocity `v=0ms^(-1)`
Acceleration of the object `a=-g=-9.8ms^(-2)` (upward motion)
(i) `v^(2)=u^(2)+2as`
`0=u^(2)+2 xx (-9.8 ms^(-2)) xx 10m`
`-u^(2)=-2 xx 9.8 xx 10m^(2) s^(-2)`
`u=sqrt(196) ms^(-1)`
`u=14ms^(-1)`
(ii) u=v+at
`0=14ms^(-1)-9.8ms^(-2) xxt`
t=1.43s
Thus, (i) Initial velocity `u=14ms^(-1)`
(ii) Time taken t=1.43s