Question

An object is thrown with velocity 30 m/s. how much time does it take to come to the thrower?

Answer 1

is it thrown vertically up ??

then

u = 30 m/s

Time of flight = time taken by the object to come back to the thrower = 2u/g = 2×30 / 10 = 6 seconds .

Reference : CBSE class 11 Rectilinear motion

Hope this would be helpful ..

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Answer 2

We know that:

$\huge\boxed{\sf{v = u + gt}}$

$\implies$ 9.8 × t = 30

$\implies$ t = 30 / 9.8

$\implies$ t = 3.06 s

If time for:

$\boxed{\sf{Upward\:direction = Downward\:direction}}$

Then:

Total time taken by a ball to return back:

$\implies$ 3.06 + 3.06

$\implies$ 6.12 seconds

Final answer: 6.12 sec