12th grade

posted by .

Wheat is falling from a chute onto a level floor at a rate of 8pi ft3/min to form a conical pile. If the height of the pile is always equal to the radius of its base, at what rate is the radius increasing when the pile is 8 ft deep?

  • 12th grade -

    V = (1/3)πr^2h
    but h=r
    V= (1/3)πr^3
    dV/dt = πr^2 dr/dt
    so when h = 8 , r = 8 and dV/dt = 8π

    8π = π(8)^2 dr/dt
    dr/dt = 8π/(64π) = 1/8 ft/min

  • 12th grade -

    THANKS!

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. AP Calculus

    Sand pouring from a chute forms a conical pile whose height is always equal to the diameter. If the height increases at a constant rate of 5 ft/min, at what rate is sand pouring from the chute when the pile is 10 ft high?
  2. AP Calculus

    Wheat is poured through a chute at the rate of and falls in a conical pile whose bottom radius is always half the altitude. How fast will the circumference of the base be increasing when the pile is 8 ft high?
  3. Math

    Corn is poured through a chute at the rate of 10ft^3 / min and falls in a conical pile whose bottom radius is always half the height. How fast is the circumference of the base changing when the pile is 8 feet high?
  4. Related rates

    Sand is being dropped at the rate of 10 cubic meter per minute onto a conical pile. If the height of the pile is always twice the base radius, at what rate is the height increasing when the pile is 8 meters high?
  5. math

    San 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 (a) height and (b) radius changing when the pile is 4 m height?
  6. calculus

    Sand falls from a conveyor belt at a rate of 20 m^3/min onto the top of a conical pile. The height of the pile is always 3/4 of the base diameter. Answer the following. a.) How fast is the height changing when the pile is 10 m high?
  7. calculus

    grain is being poured through a chute at rate of 8 ft^3/min and forms a conical pile whose radius of the bottom is always 1/2 the height of pile. How fast is circumference increasing when the pile is 10 feet high?
  8. Timerate problem(calculus)

    Sand is being dropped at the rate 10 metercube/min onto a conical pile. If the height of the pile is always twice the base radius, at what rate is the increasing when the pile is 8 m high?
  9. Calculus

    Sand falls from a conveyor belt onto a conical pile at a rate of 6ft/mi^3. The radius of the base is always equal to two-thirds of the pile’s height. At what rate is the height of the pile changing when the radius of the base of …
  10. Time rates

    sand is being dragged at the rate of 10m^3/min into a conical pile. if the height of the pile is always twice the base radius, at what rate is the height increasing when the pile is 2m high?

More Similar Questions