Question

A book is dropped from the building top and reaches the ground in 8Seconds. Find the velocity with which it will hit the ground if the value of'g' is 9.8 m/s2.​

Answer 1

Answer:

81

Explanation:

Answer 2

Given :

Time taken by book to reach ground = 8s

To Find :

Velocity with which book hit the ground.

Solution :

■ First of all we need to find height of the building.

• Since acceleration due to gravity has constant magnitude, we can apply equation of kinematics to solve this problem.
• For a body falling freely under the action of gravity, g is taken positive$.$

❇ Second equation of kinematics :

➠ H = ut + 1/2 gt²

For free falling object : u = 0

➠ H = 1/2 gt²

➠ H = 1/2 (9.8)(8)²

➠ H = 313.6m

❇ Third equation of kinematics :

➠ v² - u² = 2gH

➠ v² = 2gH

➠ v² = 2 × 10 × 313.6

➠ v² = 6272

➠ v = 79.19 m/s