Answer:
Step-by-step explanation:
We shall find first the velocity of ball at the time when string breaks. Let it be v . During its fall on the ground , 1.02 m below, we use the formula 
h = 1/2 gt² where t is time of fall . 
1.02 = 1/2 x 9.8 x t²
t²= .2081
t = .456 
During this time it travels horizontally at distance of 2.5 m with uniform velocity of v 
 v x .456 = 2.5 
v = 5.48 m /s 
centripetal acceleration 
= v² / r where r is radius of the circular path 
= 5.48² / .478 
= 62.82 m /s²