Answer:
a. The speed of the cylinder has decreased.
c. The magnitude of the acceleration of the cylinder has decreased.
Explanation:
Lets take angular speed of the turn table = ω
Linear speed at distance r from center of turn table
V= ω r
The linear speed of the cylinder at distance R
r=R
V= ω R
When the distance become R/2 ,then new linear speed
r=R/2
V'= ω R/2
V'= ω R/2 = V/2
V'=V/2
Therefore speed of the cylinder is decreases.
The radial acceleration a
a= ω² r
When r decrease then the magnitude of the cylinder will decreases.
Therefore option a and c is correct.