A community for students.
Here's the question you clicked on:
 0 viewing
anonymous
 4 years ago
Please help on related rates i do not get it
A light is fastened on a rolling cart 1m above the floor. The light moves at 2m/s towards a 2m tall man standing 4m from a wall. How fast is the tip of the mans shadown on the wall moving when the light is 7m from the wall?
anonymous
 4 years ago
Please help on related rates i do not get it A light is fastened on a rolling cart 1m above the floor. The light moves at 2m/s towards a 2m tall man standing 4m from a wall. How fast is the tip of the mans shadown on the wall moving when the light is 7m from the wall?

This Question is Closed

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0This resource will help you with these kinds of problems: http://www.intmath.com/applicationsdifferentiation/4relatedrates.php. Generally the first step with these kinds of problems is to simply draw a picture. In this case the picture will look something like this:

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0dw:1354327393530:dw

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0So what we have done in this picture already is that we have found the variables and the constants of the problem. The variables being x & y and the constants being the measurements given in the picture and speed that the cart is moving at. Note that the speed is given as 2. It is negative because as the cart moves closer to the man, x gets smaller. We will refer to the speed of the cart as: \[\frac{ dx }{ dt }\] (change in x with respect to t or time)

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0The next step now is to build a mathematical relationship between x and y. Looking at the picture we can see that there is actually a triangle inside a triangle (see http://www.youtube.com/watch?v=1T9dHMU5pkk). So we can then say: \[\frac{ y1 }{ 1 }=\frac{ 4+x }{ x }\] We say y 1 because we don't want to the first meter and we define y to start from the ground up, not from the height of the light.

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0See how you go from here and let me know if you get stuck and i will give you some more help =)
Ask your own question
Sign UpFind more explanations on OpenStudy
Your question is ready. Sign up for free to start getting answers.
spraguer
(Moderator)
5
→ View Detailed Profile
is replying to Can someone tell me what button the professor is hitting...
23
 Teamwork 19 Teammate
 Problem Solving 19 Hero
 Engagement 19 Mad Hatter
 You have blocked this person.
 ✔ You're a fan Checking fan status...
Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.