# In 3001: The final odyssey, Arthur C. Clarke writes of a tower that stretches from in Earth’s equator to geosynchronous orbit. (a) The hero, Frunk Poole, finds himself in the tower and estimates the acceleration of free fall at his altitude to be g/2. Taking into account rotational motion, what is Poole’s altitude? (b) Calculate the work necessary to raise a 100-kg mass from the surface of the Earth up through the tower to the geosynchronous altitude. Compare your result in the energy expenditure of a rocket that can do the same thing today, (Hint: Assume that the rotational correction is small, and solve iteratively.)

Kevin Nash
askIITians Faculty 332 Points
8 years ago
The gravitation acceleration on the surface of the neutron star is equal to the free-fall acceleration on its surface. Any object falling on the neutron star will accelerate at its free-fall acceleration. As the object fell from rest, its final velocity is equal to zero. The mass of the Sun is about . 99 × 1030 kg.

(a) The gravitation acceleration at the surface of the neutron stars is equal to its free-acceleration on its surface.
Thus, the gravitation acceleration is