Question

A fire cracker is
fired and it rises do
height of 1000m. find the velocity
by which it was released and the
time taken by it
to reach the
highest point
(take a = 10m/s^2)
​

Answer 1

Answer:

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)

Step-by-step explanation: