Word problem using derivatives - struggling with it

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SUMMARY

The discussion centers on applying derivatives to Boyle's Law, represented by the equation PV = c, where P is pressure, V is volume, and c is a constant. The user seeks assistance in determining the rate of change of pressure (dp/dt) when the volume is decreasing at a rate of 10 cm³/min, with initial conditions of pressure at 100 g/cm² and volume at 20 cm³. The correct approach involves using the product rule for differentiation, leading to the equation dp/dt = - (P/V) * (dv/dt). This formula allows for the calculation of dp/dt by substituting the known values.

PREREQUISITES
  • Understanding of Boyle's Law and its mathematical representation
  • Knowledge of derivatives and differentiation techniques
  • Familiarity with the product rule in calculus
  • Ability to solve algebraic equations
NEXT STEPS
  • Study the product rule in calculus for differentiating products of functions
  • Practice solving related rates problems in physics
  • Explore applications of Boyle's Law in real-world scenarios
  • Learn how to apply derivatives in various physical contexts
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Students studying calculus, particularly those focusing on applications of derivatives in physics, as well as educators seeking to clarify concepts related to Boyle's Law and related rates.

meredith
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Homework Statement



the equation is PV = c; p = pressure, v = volume, c=constant. (also known as Boyle's law)
the question: if volume is decreasing at a rate of 10cm^3/minute, how fast is the pressure increasing when the pressure is 100g/cm^2 and volume is 20 cm^3


Homework Equations



none


The Attempt at a Solution


dv/dt = -10cm^3/min
dp/dt = ?
equation: PV=c
derivative:
dp/dt x dv/dt = 0
dp/dt = -dv/dt

but i know what I am doing isn't right. can anyone help me? THANKS!
 
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meredith said:

Homework Statement



the equation is PV = c; p = pressure, v = volume, c=constant. (also known as Boyle's law)
the question: if volume is decreasing at a rate of 10cm^3/minute, how fast is the pressure increasing when the pressure is 100g/cm^2 and volume is 20 cm^3


Homework Equations



none


The Attempt at a Solution


dv/dt = -10cm^3/min
dp/dt = ?
equation: PV=c
derivative:
dp/dt x dv/dt = 0
The above isn't right. It is not true that d/dt(PV) = dP/dt * dV/dt. You need to use the product rule.
meredith said:
dp/dt = -dv/dt

but i know what I am doing isn't right. can anyone help me? THANKS!

After you differentiate PV, solve algebraically for dP/dt, and then substitute the values you have.
 

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