In the figure, a sphere of radius 2 m rolls on a plank. The accelerations of the sphere and the plank are indicated. The value of α is
2rad/s2
4rad/s2
3rad/s2
1rad/s2
As sphere rolls, the lowest point of the sphere should have the same acceleration as the plank.
Hence, a1=αR−a22=2α−4 ⇒ α=3rad/s2