Assume that the earth goes round the Sun in a circular orbit with a constant speed of 30 km/s.
(a) the average velocity of the earth from 1st Jan, 90 to 30th June, 90 is zero.
(b) the average acceleration during the above period is 60 km/s².
(c) the average speed from 1st Jan, 90 to 31st Dec, 90 is zero.
(d) the instantaneous acceleration of the earth points towards the sun.
Answers
Answer ⇒ Option (d). The instantaneous acceleration of the earth points towards the sun.
Explanation ⇒ As the Earth goes around the sun, its Average Velocity is zero in one complete round. But in the given cases of the Option (a). the average velocity cannot be zero since, there is only half period of revolution of earth. This means the displacement will be twice the distance between sun and earth.
In Option (c). Average speed can never be zero.
For Option (b). The average acceleration of the Earth is 6 moths (since the period is of 6 months as given in question) will be much less than 60 km/s².
Now, Option (d). will be correct because the Instantaneous acceleration of the Earth will always be pointed out towards the sun.
Hope it helps.
Option (d). The instantaneous acceleration of the earth points towards the sun.