A) 4 ms
B) 40 ms
C) 400 us
D) 1s
Correct Answer: A
Solution :
Given that, s =1.2 m and \[v=640\,m{{s}^{-1}}\,a=?;\,u=\,0;t=?\] We have the third equation of motion \[2as={{v}^{2}}-{{u}^{2}}\] \[2a\times 1.2=640\times 640\] or \[a=\frac{8\times 64\times {{10}^{3}}}{3}\]and by first equation of motion\[v=u+at\]or \[t=\frac{v}{a}=\frac{15}{4}\times {{10}^{-3}}=3.75\times {{10}^{-3}}s\approx \,4\,ms.\]You need to login to perform this action.
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