The average distance between earth and the sun is 1.5 ✕ 1011 m. (a) calculate the average speed of earth in its orbit (assumed to be circular) in meters per second.

29865.31 m/s

Explanation:

Radius of the Earth orbit if it is assumed to be circular = 1.5×10¹¹ m = r

Circumference of the orbit = 2πr

= 2π×1.5×10¹¹

= 3π×10¹¹ m

Time taken by Earth to complete one rotation around the orbit = 365.25 days

Converting to seconds we get

365.25×24×60×60

= 31557600 seconds

Velocity of Earth

∴ The average speed of Earth in its orbit is 29865.31 m/s

what was the answer?

5 w for 1hr = 5x60x60 joules=300x60=3000x6=18,000j as total energy conversion. efficiency of bulb needed for radiant to thermal within 18000