# Thread: angular speed, tangetial speed.

1. ## angular speed, tangetial speed.

The earth orbits the sun once a year (3.16 x 10^7 s) in a nearly circular orbit radius 1.50 x 10^11 m. With respect to the sun, determine the following.

(a) the angular speed of the earth

(b) the tangential speed of the earth
m/s

(c) the magnitude and direction of the earth's centripetal acceleration magnitude m/s^2

i don't understand why a kinematic equation does not work for this.

2. anyone around to grab this one please?

3. Originally Posted by rcmango
The earth orbits the sun once a year (3.16 x 10^7 s) in a nearly circular orbit radius 1.50 x 10^11 m. With respect to the sun, determine the following.

(a) the angular speed of the earth
$\displaystyle \dot{\theta}=2\pi/\tau = 2\pi/[3.16\times 10^7]$ rad/s

(b) the tangential speed of the earth
m/s
$\displaystyle v_{tang}=r \dot{\theta}$

(c) the magnitude and direction of the earth's centripetal acceleration magnitude m/s^2
Direction is radialy inwards and its magnitude is:

$\displaystyle a_{centripedal}=v_{tang} \dot{\theta}$

RonL

4. i'm not sure how the answer is reached by the above calc, but 1.99e-07 is correct. for the first one. i got 4.186E-11 ?

5. Originally Posted by rcmango
i'm not sure how the answer is reached by the above calc, but 1.99e-07 is correct. for the first one. i got 4.186E-11 ?
There was a type (now corrected) but you should be on the look out for these.

RonL