The Total solution for NCERT class 6-12
Choose the correctalternative:
(a) If the zero of potentialenergy is at infinity, the total energy of an orbiting satellite is negative ofits kinetic/potential energy.
(b) The energy required tolaunch an orbiting satellite out of earth’s gravitational influence ismore/less than the energy required to project a stationary object at the sameheight (as the satellite) out of earth’s influence.
(a) Kinetic energy
(b) Less
(a) Total mechanicalenergy of a satellite is the sum of its kinetic energy (always positive) andpotential energy (may be negative). At infinity, the gravitational potentialenergy of the satellite is zero. As the Earth-satellite system is a boundsystem, the total energy of the satellite is negative.
Thus, the total energy ofan orbiting satellite at infinity is equal to the negative of its kineticenergy.
(b)An orbiting satellite acquires a certain amount of energy that enables it torevolve around the Earth. This energy is provided by its orbit. It requiresrelatively lesser energy to move out of the influence of the Earth’sgravitational field than a stationary object on the Earth’s surface thatinitially contains no energy.