In non-uniform circular motion, the net acceleration of the particle is directed: MCQ with Answer and Explanation

Explanation:
Enrico Fermi led the team that constructed 'Chicago Pile-1', which achieved the world's first artificial, self-sustaining nuclear chain reaction on December 2, 1942. This was the first nuclear reactor. While he worked on the Manhattan Project (atomic bomb), his crowning individual distinction is creating the first controlled reactor.

Explanation:
Density = 80/100 = 0.8 g/cc. Water density 1 g/cc. Fraction submerged = 0.8, so 80 cc submerged, 20 cc above. So option B correct.

Explanation:
Work (W) = F × d × cos(θ). In scenario A, displacement (d) is zero. In scenario B, the applied force (upward) is perpendicular to the displacement (horizontal), so cos(90°) = 0. In scenario C, the centripetal force (gravity) is perpendicular to the satellite's instantaneous direction of motion, so work done is zero. All cases yield zero work.