Question

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 1

Answer:

1) 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 + 2as

0 = u^2- 2*9.8*1000

-u^2= -19600

u^2= 19600

u=140 m/s

(2) u=140 m/s (as calculated above)

   1st equation of motion,

v= u+at

0=140+(-9.8)t

-140= -9.8t

140= 9.8t

t=  1400/98

t=  14.3 seconds

t= 14 seconds( approximately)

     

Answer 2

Answer:

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