The ideal mechanical advantage of a lever (IMA) is given by:

Where:
Le = Effort of the arm
Lr = Resistance arm.
Therefore, we can increase the force adventage by increasing the effort arm or reducing the load arm
Answer:
a. Make the effort length longer.
Answer
given,
initial speed of merry-go-round = 0 rad/s
final speed of merry-go-round = 1.5 rad/s
time = 7 s
Radius of the disk = 6 m
Mass of the merry-go-round = 25000 Kg
Moment of inertia of the disk


I = 450000 kg.m²
angular acceleration



we know,



By V=IR
A: 24=I*20
I = 1.2A
B: 220 = I*250
I = 0.88A
C: 6= I*3
I = 2 A
C,A,B