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An egg was dropped from the top of a 30 m building. What is its speed just before hitting the ground


Sagot :

Answer:

Height of the building = h = 30 m

Initial speed, when dropping = 0

Speed just before hitting the ground = v =?

Acceleration due to gravity = g =9.8 ms-2 or if you wish,you can use 10 ms-2

Solution

Applying law of conservation of energy:

Kinetic energy just before hitting the ground = the potential energy when releasing it.

1/2mv^2 = mgh

v =sqrt of (2gh) = sqr(2x9.8x30) =24.24 =24 m/s

(Answer corrected to two significant figures, because the given data is correct to 2 significant figures. )

Alternatively you can use,

v^2 = u^2 + 2as

Where v = ?, u =0, a =g = 9.8 or 10 ms^2

Substitute the values and get the answer.