# Homework Help: Find distance, velocity vectors

1. Sep 23, 2006

### kbowman

Hi there, I really need help with this one part of an assignment! We never covered this in my lectures, however I have an assignment due on this.. which is not impressing me.
Even if you should tell me step by step on how I could answer this, or show me via examples used in the problem, I would be forever grateful!
Kat

2. Sep 24, 2006

### andrevdh

Ex. 2
(a) Have a go at this and we will help you to do it. Show your attempt at this part of the problem in a post here.
(b) This part requires you to use the relationship between an angular measure in a different unit, radians, not degrees. Lets say the angle is at a point A. The two arms of the angle extend outwards. You are required to determine the angle in radians of this angle. First you draw a circle with point A as the centre through the two arms. The radius of the circle is r. The circle cut the two arms at the points B and C. You need to determine the distance s along the circle between the two points B and C. The angle in radians is then given by

$$\theta _r = \frac{s}{r}$$

This angular measure have no dimension as you see. For an angle of $360^o$ it comes to $2\pi$ radians (see if you can get this yourself).

To solve this part convert the given angle to radians and then calculate the arc distance with the known radius.

To convert from degrees to radians note that you need to calculate the angle in degrees by a conversion factor of ''units" [radians per degree]. From the example above this conversion factor will come to

$$\frac{2\pi}{360^o}$$

Last edited: Sep 24, 2006