# Constant speed and velocity

1. Oct 8, 2008

### chanv1

A car travels due east with a speed of 50.0 km/h. Raindrops are falling at a constant speed vertically with respect to the Earth. The traces of the rain on the side windows of the car make an angle of 45.0° with the vertical. Find the velocity of the rain with respect to the following reference frames.
(a) the car _____m/s

(b) the Earth ____ m/s

Any help would be greatly appreciated!

2. Oct 9, 2008

### CompuChip

The velocity of the raindrops relative to the car is the vector sum of the velocity of the rain with respect to the earth and the car with respect to the earth.

In formula:
$$\vec v_\mathrm{r,c} = \vec v_\mathrm{r,e} + \vec v_\mathrm{e,c}$$

3. Oct 9, 2008

### Danger

Good response, CompuChip, but this belongs in the Homework Help section. It should be moved. Nothing wrong with the question or the answer—it's just in the wrong place.