Question

if the distance between Earth and the Sun were half of its present value how many number of days will be there in a year.. Hint.. Use keplers third law

Answer 1

Hi friend 

Here is your answer,

Average radius of earths orbit=14,96,00,000
Earth's revolution speed=30 km/s
 
In this  case,Earth is rotating with the same speed ,but the distance from the sun is half of the current distance.

14,96,00,000/2=74800000

Circumference of Earth's orbit=2*π*r=2*3.14*74800000=469744000 km

Time required to cover this distance with the speed of 30 km/s  will be =469744000/30=15628133.33 seconds=4349.4814 hours=181.22 days