গণিত প্রশ্ন

A ball is thrown horizontally with speed v from the floor at the top of some stairs as shown in the figure given below. The width and height of each step are both equal to l l . What should v be so that the ball barely clears the corner of the step that is 4 steps down? Assume l=25 cm l = 25 \text{ cm} and g=10 ms−2 g = 10 \text{ ms}^{-2} .