A stone thrown vertically upwards takes 4 s to retun to the throer. Calculate a) initial velocity of stone and b) maximum height attained by the stone (g=10 m/s²).

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Solution

Dear student,

(a) Consider,

upward gravity = -10 m/s2

Total time (to and fro)= 4 s, so, upward journey = 4/2 = 2 s

Initial velocity (u) = ?

Final velocity (v) = 0 m/s

From First equation of motion,

Final velocity = Initial velocity +gt

or, 0 = u + (-10 X2)

or, u = 20m/s

So, The velocity at which ball is thrown in the upward direction is 20 m/s.

(b) the maximum height (hmax) is reached by a stone

Second equation of motion

s = ut + 1/2 gt2

here s = the maximum height (hmax)

or , hmax =(20 X 2) + 1/2 (-10)(2)2

hmax = 20 m

regards

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A stone thrown vertically upwards takes 4 s to retun to the throer. Calculate a) initial velocity of stone and b) maximum height attained by the stone (g=10 m/s2).

A stone thrown vertically upwards takes 4 s to retun to the throer. Calculate a) initial velocity of stone and b) maximum height attained by the stone (g=10 m/s²).