Question

A stone thrown upward with a speed u from the top
Jof a tower reaches the ground with a velocity 4u. The
height of the tower is​

Answer 1

Answer:

According to Third Equation of Motion,

⇒ v² - u² = 2as

According to the question,

⇒ Initial Velocity = u

⇒ Final Velocity =4u

⇒ Acceleration = g

Substituting in the equation we get,

⇒ ( 4u )² - u² = 2gs

⇒ s = ( 16u² - u² ) / 2g

⇒ s = ( 15 u² ) / 2g

Therefore the height of the tower is 15u²/g

Answer 2

Solution:

Given:

=> Initial velocity (u) = u.

=> Final velocity (v) = 4u.

=> Acceleration (a) = g.

To find:

=> Height of the Tower.

So,

By using 3rd equation of motion in terms of gravitation,

=> v² = u² + 2gh

=> (4u)² - u² = 2gh

=> 16u² - u² = 2gh

=> 15u² = 2gh

=> h = 15u²/2g.

So, Height of the tower is 15u²/2g.