Recent content by louloulou

I'm not sure when I should be plugging in the "2.00 s" Anyway, this is what I did. 2 (31.6) dh/dt = 2(30) + 2 (20) dh/dt = 1.38 But something is not right because I still need to do something with the 2.00 seconds:rolleyes:

I know this is wrong...i'm getting 1.38 m/s later. Can you please tell me your answer so I can at least compare with mine?

Okay, well thanks for all your help i'll give that a try and post it again.

So... h^2 = 30^2 + 20^2 h = 36.1 dh/dt and then... 2h(dh/dt) = 2x(dx/dt) + 2y(dy/dt) I'm getting confused as to what the x and y is now..still 40(x) & 20(y)? Ugh, I don't know! :confused:

I'm sorry, I don't quite understand. What do I need to change? Is the 54 dh/dt not correct (Should it just be 30^2 + 20^2 ?)

Homework Statement An elevated train on a track 30.0 m above the ground crosses a street (which is at right angles to the track) at the rate of 20.0 m/s. At that instant, an automobile, approaching at the rate of 30.0 m/s, is 40.0 m from a point directly beneath the track. Find how fast...