Question

A stone is thrown downward straightly its speed at speed of 20 second what and it reaches the ground at 40 metre second what will be the height of building

Answer 1

CORRECT QUESTION

A stone is thrown Downward with the Velocity of 20m/s and it reaches the ground at the Velocity of 40m/s. What will be the height of Building.

GIVEN:-

• $\rm{Initial\:Velocity = 20m/s^{-1}}$

• $\rm{Final\:Velocity = 40m/s^{-1}}$

• $\rm{Acceleration\:due\:to\:Gravity = +10m/s^{-2}}$.

TO FIND:-

• The height of the tower.

FORMULAE USED:-

• ${\huge{\boxed{\rm{v^{2} - u^{2} = 2as}}}}$

Where,

v = Final Velocity

u = Initial Velocity

a = Acceleration

S = height.

Now,

$\implies\rm{ v^2 - u^2 = 2gh}$

$\implies\rm{ (40)^2 - (20)^2 = 2\times{10}\times{h}}$

$\implies\rm{1600 - 400 = 20h}$

$\implies\rm{ 1200 = 20h}$

$\implies\rm{ h = \dfrac{1200}{20}}$

$\implies\rm{ h = 60m}$.

Hence, The height of the tower is 60m.

Answer 2

Correct Question:

A stone is thrown downward straightly its speed at speed of 20 m/s what and it reaches the ground at 40 m/s. What will be the height of building?

Answer:

60 m

Explanation:

Given; initial velocity of the stone is 20 m/s and final speed is 40 m/s.

Using the third equation of motion,

v² - u² = 2as

We know that acceleration due to gravity is 9.8 m/s² ~ 10 m/s².

Substitute the values,

→ (40)² - (20)² = 2(10)s

→ 1600 - 400 = 20s

→ 1200 = 20s

Divide by 20 on both sides,

→ 1200/20 = 20s/20

→ 60 = s

Hence, the height of the building is 60 m.