For a concave mirror, the radius of curvature is twice the focal length of the mirror:

where f, for a concave mirror, is taken to be positive.
Re-arranging the formula we get:

and since the radius of curvature of the mirror in the problem is 24 cm, the focal length is
Answer:
w = 0.189 rad/ s
Explanation:
This exercise we work with the conservation of the moment, the system is made up of the merry-go-round and the child, for which we write the moment of two instants
Initial
L₀ = I₀ w₀
Final
= I w
L₀ = L_{f}
I₀ w₀ = I_{f} w
.w = I₀/I_{f} w₀
The initial moment of inertia is
I₀ = 500 kg. m2
The final moment of inertia
= 500 + m r²
I_{f} = 500 + 20 1.5
I_{f} = 530 kg m²
Initial angular velocity
w₀ = 0.20 rad / s
Let's calculate
w = 500/530 0.20
w = 0.189 rad / s
Answer:
The axle is fixed to a frame or a block. The pulley is normally fixed to a support above the load. The load is tied to one end of the rope and the effort is applied at the other end. Such a pulley makes our work easier by simply changing the direction of the force, i.e. a load is lifted up using a downward effort.
May be this will help U