Question

a ball rolls horizontally off the top of a stairway with a speed of 1.52 m/s. the steps are 20.3 cm high and 20.3 cm wide. which step does the ball hit first?

Answer 1

3rd step will be the ball hit first.

See the attachment.

Answer 2

its a question of projectile motion

initial velocity of ball is 1.52 m/sec in horizontal direction

the steeps are 20.3m high

 time take to fall this distance is

  h= 1/2gt2

 20.3 =1/2 *10 *t2

 t= 2.015 sec

in this time horizontal distance travel = 1.52 * 2.015 =3.063 m

Since distance is less than 20.3  so ball hit the first step.