Question

A ball is dropped from a tower reaches the ground after 5seconds. Find:-

Height of tower and Velocity if body when It reaches ground

Answer 1

Given:

• Time taken to reach ground= t = 5sec

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Need to find:

• Height of tower =h =?
• Velocity of body when it reaches the ground = v =?

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Solution:

We know, for an object which is dropped from height,

$T = \sqrt{ \dfrac{2h}{g} }$

$\implies {T}^{2} = \dfrac{2h}{g}$

$\implies h = \dfrac{g {T}^{2} }{2}$

$\implies h = \dfrac{10 \times 5 \times 5}{2} m$

$\red{\bold{\boxed{\large{\implies h = 125m}}}}$

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We know,

Velocity = $\sqrt{2gh}$

$\implies v \: = \sqrt{2 \times 10 \times 125}$

$\implies v = \sqrt{2500} m/s$

$\red{\bold{\large{\boxed{\implies v = 50 \: m/s}}}}$

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▪Height of tower is 125m and velocity when the body reaches the ground is 50m/s