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Chapter 1: Q20DQ (page 425)

Many people believe that orbiting astronauts feel weightless because they are 鈥渂eyond the pull of the earth鈥檚 gravity.鈥� How far from the earth would a spacecraft have to travel to be truly beyond the earth鈥檚 gravitational influence? If a spacecraft were really unaffected by the earth鈥檚 gravity, would it remain in orbit? Explain. What is the real reason astronauts in orbit feel weightless?Many people believe that orbiting astronauts feel weightless because they are 鈥渂eyond the pull of the earth鈥檚 gravity.鈥� How far from the earth would a spacecraft have to travel to be truly beyond the earth鈥檚 gravitational influence? If a spacecraft were really unaffected by the earth鈥檚 gravity, would it remain in orbit? Explain. What is the real reason astronauts in orbit feel weightless?

Short Answer

Expert verified

A spacecraft has to travel to infinity to be free from the earth鈥檚 gravitational influence. A spacecraft get affected by the gravity of earth , it will not be able to maintain its orbit in absence of earth鈥檚 gravity and the actual cause of weightless feeling of astronauts in orbit is non-contact forces.

Step by step solution

01

Introduction

At any place, there can be two types of external forces that will work upon the body of an individual.

  1. Contact forces
  2. Non-contact forces

When contact forces will work upon the body of the individuals they will feel the weight and if non-contact forces will work then they will feel weightlessness.

02

Explanation

Feeling weightless is completely a sensational experience for any person and this experience will felt by someone when there are no external contact forces are working upon that person at any place. When non-contact forces will work on someone鈥檚 body there will be no pulling or pushing action upon the body by direct touch.

Gravity is a non-contact force and any individual does not feel the weight because of the presence of the gravity so removing or adding gravitational force over an individual body will not cause the feeling of weight or weightlessness.

An individual also feels weightless during a roller coaster ride, and free-falling from any heighted place because of an absence of contact forces.

The earth鈥檚 gravitational influence will never be truly zero in space it just gets weakened when any spacecraft will travel away from the earth. So for zero gravitational influence, a spacecraft has to travel an infinite distance away from the earth.

A spacecraft get pulled towards the earth by the earth鈥檚 gravitational field when it tries to move away from the earth. Earth鈥檚 gravity maintains a balance of gravitational force of spacecraft by creating centripetal acceleration to maintain its orbit. If there will be no influence of gravity of earth the spacecraft will fall from its orbit.

03

conclusion

Hence, A spacecraft has to travel to infinity to be free from the earth鈥檚 gravitational influence. A spacecraft get affected by the gravity of earth , it will not be able to maintain its orbit in absence of earth鈥檚 gravity and the real cause of weightless feeling of astronauts in orbit is non-contact forces.

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Most popular questions from this chapter

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Consider a spacecraft in an elliptical orbit around the earth. At the low point, or perigee, of its orbit, it is 400 km above the earth鈥檚 surface; at the high point, or apogee, it is 4000 km above the earth鈥檚 surface. (a) What is the period of the spacecraft鈥檚 orbit? (b) Using conservation of angular momentum, find the ratio of the spacecraft鈥檚 speed at perigee to its speed at apogee. (c) Using conservation of energy, find the speed at perigee and the speed at apogee. (d) It is necessary to have the spacecraft escape from the earth completely. If the spacecraft鈥檚 rockets are fired at perigee, by how much would the speed have to be increased to achieve this? What if the rockets were fired at apogee? Which point in the orbit is more efficient to use?.

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