Question

A ball rolls off the top of a stairway with a horizontal velocity of 9km/h. If the steps are 15 cm high and 10 cm wide, then if the ball just hits the last step , then how many total steps are there in the stairway

Answer 1

Answer:

19

Explanation:

9km/h = 9000/3600 = 2.5 m/sec

y = gt/2 = 5t²

x = ut = 2.5t

assuming there are n steps

2.5t = 0.1n

5t² = 0.15n

2 t = 15/10 = 1.5

t = 0.75

n = 18.75 ≈ 19

total steps  in the stairway = 19