Question

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

Answer 1

Answer:

Height of the tower = 15u²/2g

Step by step explanations :

Given,

a stone thrown upward with a speed u from the top of the tower

reaches the ground with a velocity 4u

Here,

Initial velocity of the stone = u

and we know that

velocity at which is thrown upwards it passes it initial position at the same speed

so,

speed of stone in during passing it's initial position = u

so,

now we have,

Initial velocity = u

final velocity = 4u

v² = u² + 2gh

(4u)² = u² + 2gh

2gh = 16u² - u²

2gh = 15u²

h = 15u²/2g

so,

Height of the tower = 15u²/2g

Answer 2

Answer:

Height of the tower = 3u²/4

Step by step explanations :

Given,

Initial velocity of the stone = u

final velocity = 4u

v² = u² + 2gh

(4u)² = u² + 2gh

2gh = 16u² - u²

2gh = 15u²

h = 15u²/2g

h = 15u² /2 × 10

h = 3u²/4

so,

Height of the tower = 3u²/4