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. A fire cracker is fired and it rises to a height of 1000 m. Find the velocity by which it was released and the time taken by it to reach the highest point (take a = 10 m/s²)

Answer»

Explanation: h=1000m      v= 0 m/s (at highest point)       G= 9.8 m/s( taken to be negative according to sign convention)      USING 3rd equat. of motion,v^2= u^2 + 2as0 = u^2- 2*9.8*1000-u^2= -19600u^2= 19600u=140 m/s(2) u=140 m/s (as calculated above)   1st equation of motion,v= u+at0=140+(-9.8)t-140= -9.8t140= 9.8tt=  1400/98t=  14.3 secondst= 14 seconds( approximately)HOPE it will HELPS you



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