Answer:a) The linear speed of the rotating merry-go-round is 1.884 m/s.
b) The acceleration of the rotating merry-go-round device is
.
Step-by-step explanation:
a) linear speed of the device:
Distance =

Child seated 1.2 meters from the center, which means that radius ,r = 1.2 meters
Time taken to complete one revolution = 4.0 seconds

The linear speed of the rotating merry-go-round is 1.884 m/s.
b) Acceleration
Linear velocity ,v = 1.884 m/s


The acceleration of the rotating merry-go-round device is
.