The acceleration due to gravity at height ℎh is given by ℎ′=gh′=g(1−hR2), and at depth d it's gd′=g(1−dR). Equating these expressions gives g(1−hR2)=g(1−dR), which simplifies to R2h=Rd or 2ℎd=2h.
The correct answer is option (C):
In the real world, everything is always in motion. Objects move at a variable or a constant speed. When someone steps on the accelerator or applies brakes on a car, the speed of the car increases or decreases and the direction of the car changes. In physics, these changes in velocity or directional magnitude of a moving object are represented by acceleration.