physics/astronomy

[SnowOwl18]

Ok, I keep trying to do the following problem:

----The asteroid Icarus orbits the Sun like the other planets. Its period is about 410 days. What is its mean distance from the Sun?
(Hint: You can derive the mean distance with the paramters known for the Earth: Period of the earth = 365 days Mean distance from the sum = 1.5e8km)----------------


Ok, so, using Kepler's laws I took 410 days and put it to the (2/3) power...and I got 55.2 AU...one AU (astronomical unit) equals 1.5e8 km...so I multiplied 55.2 by 1.5e8 km and got 8278414420 km....or 8.28e9 km.....but the computer program says I'm wrong. Does anyone know what I'm doing wrong? Thanks.

[Parth Dave]

Hint: Look at your units.

[SnowOwl18]

which units? if one AU=1.5e8 I can multiply 55.2 by that to get the answer, right?

[Parth Dave]

What units are you supposed to use in kepler's third law?

[SnowOwl18]

oh do i have to convert 410 days to years? like 1.123 years?

[SnowOwl18]

oh that worked! Thanks for your help :D

[Parth Dave]

Yup! That's exactly right.