A) 2 s
B) 5 s
C) 7 s
D) 9 s
Correct Answer: C
Solution :
The vertical component of velocity of projection \[=-50\sin 30{}^\circ =-25\,m/s\] If t be the time taken to reach the ground, \[h=ut+\frac{1}{2}g{{t}^{2}}\] Þ \[70=-25t+\frac{1}{2}\times 10{{t}^{2}}\] Þ \[70=-25t+5{{t}^{2}}\]Þ \[{{t}^{2}}-5t-14=0\]Þ t= ? 2s and 7s Since, t = ? 2 s is not valid \ t = 7 sYou need to login to perform this action.
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