Question

Find the final velocity of the ball that is dropped from the second floor if the ball takes 18 seconds before hitting the ground. The acceleration due to gravity is g = 9.80 m/s²​

Answer 1

Answer:

• The final velocity of the ball is 176.4 m/s.

Explanation:

Given,

●Initial velocity (u) = 0 m/s

●Acceleration due to gravity (g) = 9.80 m/s²

●Time interval (t) = 18 s

Applying 1st eqn. of motion,

$\purple\bigstar$ v = u + gt

[ Putting values ]

↪ v = 0 + 9.80 × 18

↪ v = 9.80 × 18

↪ v = 176.4 m/s $\red\bigstar$

For information:

• s = ut + 1/2 at²
• v² = u² + 2as

Answer 2

Question :

Find the final velocity of the ball that is dropped from the second floor if the ball takes 18 seconds before hitting the ground. The acceleration due to gravity is g = 9.80 m/s²​

Given :

• Time taken to hit the ground (t) = 18 s
• Acceleration due to gravity (g) = 9.8 m/s²
• Initial velocity of ball (u) = 0 m/s   [∵ It is considered that ball was at rest before it was dropped]

To find :

• Final velocity of ball

Solution :

From the first equation of motion we find that ; final velocity of a body is the addition of initial velocity of body and product of acceleration & time taken. [Here, gravitational acceleration]

In equation it is,

⇒ v = u + gt   - - - - - - [1st equation of motion]

Substituting values,

⇒ v = 0 + (9.8 * 18)

⇒ v = 0 + 176.4

⇒ v = 176.4 ms⁻¹

∴ Final velocity of ball = 176.4 ms⁻¹