A ball is gently dropped from a height of 45 m. If its velocity increases uniformly at the rate of 10 m/s² with what velocity will it strike the ground?
(A) 20 m/s
(B) 30 m/s
(C) 40 m/s
(D) 50 m/s
Answers
Given:
✰ Initial velocity, ( u ) = 0 m/s
✰ Distance or the height of fall, ( S ) = 45 m
✰ Download acceleration, ( a ) = 10 m/s²
To find:
✠ The final velocity with which the ball will strike the ground.
Solution:
Let's understand the concept first! We will assume the final velocity with which the ball will strike the ground as v. As we are already provided with initial velocity, distance and download acceleration, thus by using third equation of motion, we will find the value of final velocityof the ball.
Let's find out...♪
Using third equation of motion,
✭ v² - u² = 2aS ✭
Substituting the values in the above equation, we have:
➛ v² - 0² = 2 × 10 × 45
➛ v² = 2 × 10 × 45 + 0
➛ v² = 20 × 45 + 0
➛ v² = 20 × 45
➛ v² = 900
➛ v = √900
➛ v = 30
∴ The final velocity with which the ball will strike the ground, v = 30 m/s
Option b) 30 m/s is correct ✔
_______________________________