A uniform circular disc of radius 50 cm at rest is free to turn about an axis which is perpendicular to its plane and passes through its centre. It is subjected to a torque which produces a constant angular acceleration of 2.0 rad/s². Its net acceleration in m/s² at the end of 2.0 s is approximately:

The correct option is A
8.0
Given:
Radius, R = 0.5 m
Angular acceleration, α = 2 rad/s²
Time, t = 2 s
Assumption: Acceleration asked is for a point on the rim.
After 2 s, Angular velocity is given by:
ω = ω₀ + αt
ω = 0 + 2 × 2
ω = 4 rad/s
Centripetal Acceleration is given by, ac = ω²R = 4² × 0.5 = 8 m/s²
Tangential Acceleration is given by, at = Rα = 0.5 × 2 = 1 m/s²
Net acceleration, anet = √(ac² + atan²)
anet = √8² + 1² ≈ 8 m/s²