# Displacement vectors

1. Sep 13, 2004

### quick

The minute hand on a watch is 2.0 cm in length. What is the displacement vector of the tip of the minute hand

From 8:00 to 8:20 a.m.? Express vector r in the form r_x, r_y, where the x and y components are separated by a comma.

and

From 8:00 to 9:00 a.m.? Express vector r in the form r_x, r_y, where the x and y components are separated by a comma.

I am no idea how to do these problems. could someone give some suggestions as to how to begin?

2. Sep 13, 2004

### Tide

$$\vec r(t) = \hat i L \sin \left( 2 \pi \frac {T}{12} \right) + \hat j L \cos \left( 2 \pi \frac {T}{12} \right)$$

where L is the length of the minute hand and T is the time measured in hours.

3. Sep 13, 2004

### quick

your picture doesn't seem to show up...