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Related rates question.

  • Thread starter Willowz
  • Start date
  • #1
184
1

Homework Statement


Sand falls from a conveyor belt at the rate of 10 m^3/min onto the top of a conical pile. The height of the pile is always three-eighths of the base diameter. How fast are the a) height and b) radius changing when the pile is 4m high?


Homework Equations


h = 3/8 * 2r


The Attempt at a Solution


I'm not sure where to start. I just need a small hint.
 

Answers and Replies

  • #2
Dick
Science Advisor
Homework Helper
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618
The question is giving you dV/dt. What's the equation for the volume of a cone in terms of r and h? That's a small hint.
 
  • #3
184
1
More than enough. Thanks
 
  • #4
cepheid
Staff Emeritus
Science Advisor
Gold Member
5,192
36
The rate of change of the volume of the cone is 10 m3 per minute. What is the expression for the volume of a cone in terms of its height and base radius? This will allow you determine dr/t or dh/t in terms of dV/dt.

EDIT: two minutes too late...
 

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