Answer:
 211.2 N
Step-by-step explanation:
Data provided in the question: 
Mass of child, m = 33.0 kg 
Distance from the center, r = 2.50 m
Tangential speed, v = 4.00 m/s 
Now, 
Magnitude of the centripetal force, 

 Thus, on putting the values, we get
Magnitude of the centripetal force, 
 
 
or 
Magnitude of the centripetal force, 
 = 211.2 N
 = 211.2 N