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NEET2017PhysicsGravitationActual

A rocket is intended to leave the Earth's gravitational field. The fuel in its main engine is a little less than the amount that is necessary and an auxiliary engine, (only capable of operating for a short time) has to be used as well. When is it best to switch on the auxiliary engine?

Options

  1. Aat take-off
  2. Bwhen the rocket has nearly stopped with respect to the Earth.
  3. CIt doesn’t matter.
  4. DCan’t say

Correct answer

A. at take-off

Step-by-step solution

The rocket has to reach the highest possible total energy. If the zero level of gravitational potential energy is 'infinitely' far away, then the energy of the rocket standing on the surface of the earth is negative. The energy released during the operation of the engines increases the total energy of the rocket, and the rocket can leave, the earth's gravitational field if the sum of its potential and kinetic energies becomes positive. The energy released in the course of the operation of the principal and auxiliar

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