A stone is dropped from a height of 90cm above the top of a window which is 160 cm high. The time taken by the stone to cross the window is
1/7 s
2/7 s
3/7 s
4/7 s
t1 = to come upto the window =2×90980=37sec.t2 = to come below the window =2×250980=57sect2−t1=27 sec. time to cross the window.