ANSWER

Step-by-step explanation
Parameters given:
Weight of merry-go-round, W = 822 N
Radius of merry-go-round, r = 1.95 m
Horizontal force, F = 69.3 N
Time, t = 3.61 s
Acceleration due to gravity, g = 9.8 m/s²
First, we have to find the inertia of the merry-go-round (solid cylinder):

where m = mass; r = radius
We have that the mass of the merry-go-round is:
![\begin{gathered} W=mg \\ \Rightarrow m=(W)/(g)=(822)/(9.8) \\ m=83.88\operatorname{kg} \end{gathered}]()
Therefore, the inertia is:
![\begin{gathered} I=0.5\cdot83.88\cdot1.95^2 \\ I=159.48\operatorname{kg}m^2 \end{gathered}]()
Now, we can find the angular acceleration using the relationship between inertia and force:

Therefore, the angular acceleration:

Now, we can find the angular velocity using:

Therefore, the angular velocity is:

Now, we can find the kinetic energy of the merry-go-round using:


That is the answer.