Question

A comet orbits the Sun in a highly elliptical orbit. Does the comet have a constant
(a) linear speed,
(b) angular speed,
(c) angular momentum,
(d) kinetic energy,
(e) potential energy,
(f) total energy throughout its orbit? Neglect any mass loss of the comet when it comes very close to the Sun. question 8.8 Gravitation

Answer 1

(a) according to law of conservation of angular momentum .
L = mvr = constant .
hence, comet move faster when it close from the sun and moves slower when it is farther away from the sun .
Hence, linear speed doesn't remain constant .
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(b) we know,
V = wr hence, angular speed depends upon linear speed . linear speed is variable , hence, angular speed is also variable . it doesn't remain constant.
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(C) angualr momentum ramains constant becoz external torque acting on the comet is zero.
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(d) kinetic energy = 1/2mv²
e.g kinetic energy depends upon linear speed so , kinetic energy also doesn't remain constant.
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(e) Potential energy of comet changes as its kinetic energy changes .
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(f) total energy of comet remains constant throughout its orbit.

Answer 2

here's the answer from S.L. Arora