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A balloon starts from rest,moves vertically upwards with an acceleration g//8 ms^(-2).A Find the time taken by stone to reach the grounf (g=9.8 ms^(-1)) |
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Answer» Solution :Step-1:To FIND the distance of the stone above the ground about which it BEGINS to fall from the balloon. `S=ut+(1)/(2)at^(2)` ,here,h u=0a=g/8 ` h=(1)/(2)((g)/(g))8^(2)=4g` Step-2:The velocity of the ballon at this height can be obtained from v=u+at `V=0+((g)/(g))8=g` This becomes the intial velocity `(u^(1))` of the stone as the stone falls from the balloon at the height h. `therefore u^(1)=g` Step-3:For the TOTAL motion of the stone `h(1)/(2)"gt"^(2)-u^(1)t` Here, h=4g,`u^(1)`=g,t=time of travel of stone. `therefore -4g="gt"-(1)/(2)"gt"^(2) ""therefore-2t-8=` Solving for .t. we get t=4 and -2s. IGNORING negative value of time,t=4s |
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