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InterviewSolution
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An object thrown vertically upwards reaches a height of 500m. What was its initial velcoity? How long will the object take to come back to the Earth? Assume `g=10m//s^(2)` |
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Answer» Given: Displacement `(s)=500m` Gravitational acceleration `(g)=-10m//s^(2)` Final velocity `(v)=0m//s` To find: Initial velocity `(u)=?` `t_("total")=?` Formulae: `v^(2)=u^(2)+2gs, t_("total")=2t` `v=u+"gt"` `:.v,g` and s is given, to find u we use 3rd equation Solution: `v^(2)=u^(2)+2gs` `0=u^(2)-10000` `10000=u^(2)` `u=100m//s` Since, we have v,u and g to find t we use 1st equation `v=u+"gt"` `0=100+(-10)xxt` `10t=100` `t=10s` Time of ascent `=` Time of descent `:.t_("total")=2xx10` `:.t_("total")=20s` Initial velocity was 100 m/s and time taken to come back to Earth is 20s. |
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