If a book is knocked off a desk that is. 75 m tall at a rate of 2.0 m/s, how far away from the desk does it fall

Answer: 0.8 m

Explanation:

In the vertical direction, the speed is zero, u = 0.

Distance covered in the vertical direction, s = 0.75 m.

The book would fall with acceleration due to gravity in the vertical direction, a = g = 9.8 m/s²

From the equation of motion,

s = u t + 0.5 a t²

Substituting the above values, we will find out the time taken for the book to hit the ground.

⇒0.75 m=0+0.5*9.8 m/s²*t²

⇒t = √0.153 = 0.39 s ≈ 0.40 s

Now, the horizontal distance covered,

d = v*t ⇒d = 2.0 m/s * 0.40 s = 0.8 m

Hence, the book falls 0.8 m away from the desk.