A) 1 s
B) 2 s
C) 3 s
D) 4 s
Correct Answer: D
Solution :
\[S=ut+\frac{1}{2}g{{t}^{2}}\] or \[40=-10\,t+\frac{10}{2}{{t}^{2}}\] or \[{{t}^{2}}-2t-8=0\] or \[(t+2)(t-4)=0\] \[\Rightarrow \,\,t=4\,s\] t cant be negative.You need to login to perform this action.
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