Question

The earth moves round the sun once in year with a speed of 30 km/sec.What is the centripetal acceleration of earth towards the sun?

• A. $6\times {10}^{-7}m/s^2$
• B. $6\times {10}^{-6}m/s^2$
• C. $6\times {10}^{-5}m/s^2$
• D. $6\times {10}^{-3}m/s^2$

Answer 1

The correct option is D $6\times {10}^{-3}m/s^2$

$V_e=3\times {10}^{4}m/s$

Light takes 8 minutes from sun to reach earth.Therefore ,distance between earth and sun =$d=c\times t=3\times {10}^8\times 8\times 60=144\times {10}^{9}m$

Now,Centripetal accelaeraration is:$a=\frac{v^2}{d}$

$=\frac{9\times {10}^8}{144\times {10}^9}=6.25\times {10}^{-3}\simeq 6\times {10}^{-3}m/s^2$