Rate of how fast a shadow grows as you walk

Re: Rate of how fast a shadow grows as you walk

You're almost there! The term dA/dt is the rate of change of length A per unit time, which is precisely the velocity of point A. You were told the velocity of A is 5 ft/s, so there you go:

dB/dt = 2/3 dA/dt = 2/3 (5 ft/s) = 10/3 ft/s.

Re: Rate of how fast a shadow grows as you walk

Quote:

Originally Posted by

**daigo** Now how do I find the derivative of 'A'? It must have something to do with the movement velocity because it was given information and I haven't used it yet.

Yes... what is the meaning of A' ...?

The derivative of A wrt t...

the rate of change of distance wrt time...

what we normally call...