question_answer

A body is thrown horizontally from the top of a tower of height 5 m. It touches the ground at a distance of 10m from the foot of the tower. The initial velocity of the body is\[(g=10\text{ }m/{{s}^{2}})\]

A) 2.5 m/s            

B)      5 m/s   

C)      10 m/s              

D)      20 m/s

Correct Answer: C

Solution :

Invoking \[S=ut+\frac{1}{2}a{{t}^{2}}\]in the vertical direction \[-S=-\frac{1}{2}\times 10{{t}^{2}}\Rightarrow t=1\,s\] Along the \[x-\]axis \[10=u\times t\] or, \[u=\frac{10}{t}=\frac{10}{1}=10\,m/s.\] Hence, the correction option is (c).