Question

What is the velocity of a ball right before it hits the ground if it falls from a 2.5 m bookshelf?

Answer 1

vf = 7 m/s

Step-by-step explanation:

The final velocity of the ball right before it hits the ground can be found by using the third equation of motion:

`2gh = v_f^2 - v_i^2`

where,

g = acceleration due to gravity = 9.81 m/s²

h = height = 2.5 m

vf = final velocity = ?

vi = initial velocity = 0 m/s

Therefore,

`2(9.81\ m/s^2)(2.5\ m) = v_f^2 - (0\ m/s)^2\\v_f = √(49.05\ m^2/s^2)\\`

vf = 7 m/s