# How the velocity of rain relative to the driver in car increases?

1. Sep 19, 2014

### Krishna Behera

How does the velocity of the rain with respect to the car get added up? Velocity of rain with respect to man is given by the (velocity of rain wrt ground - the velocity of car wrt ground). Here it's not being added up!

2. Sep 19, 2014

### Orodruin

Staff Emeritus
How is what you just described not an addition of velocities?

3. Sep 19, 2014

### A.T.

You mean because there is a minus sign? Then write it like this:

velocity of rain wrt car = velocity of rain wrt ground + the velocity of ground wrt car

4. Sep 19, 2014

### CWatters

5. Sep 19, 2014

### gsal

I think the "wrt" part is basically saying to only use the horizontal components.

6. Sep 19, 2014

### Orodruin

Staff Emeritus
wrt is "with respect to" and has nothing to do with projecting out the horizontal components.

7. Sep 19, 2014

### CWatters

I think we need the OP to come back with more info on the problem.

8. Sep 19, 2014

### A.T.

That is of course true and how my post #3 should be interpreted.