Question

An object is projected upwards with velocity of 100ms .it will strike the ground after

Answer 1

v = u+at

v= 0 at topmost point

a=-10.

100=10t

t=10 sec to reach topmost pt.

so total time to reach ground =2t = 20 s

Answer 2

Answer:

An easy formula is , t = 2u / g

This is derived as ,

total time = time of ascent + time of decent

T = u/g + u/g

  = 2u / g

here ,

u = 100 m/s

g = 10 m/s²

T = 2u / g

  = 2×100 / 10

  = 20 sec

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