- #1
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I'm struggling with section a. This is my calculation:
The expression remains depend on the variable t, while in the answer is a concrete number:
Calculus Problem: Blowing Up a Spherical Balloon
- Thread starter Idan9988
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I'm struggling with section a. This is my calculation:
The expression remains depend on the variable t, while in the answer is a concrete number:
- #2
pasmith
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[itex]r = r_0 + 0.9t[/itex] is only valid if [itex]dr/dt[/itex] is constant.
Why did you assume that [itex]dr/dt[/itex] was constant? The question only tells you that [itex]dr/dt = 0.900\,\mathrm{cm}/\mathrm{s}[/itex] when [itex]r = 6.50\,\mathrm{cm}[/itex].
Why did you assume that [itex]dr/dt[/itex] was constant? The question only tells you that [itex]dr/dt = 0.900\,\mathrm{cm}/\mathrm{s}[/itex] when [itex]r = 6.50\,\mathrm{cm}[/itex].
- #3
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Agree,
The answer (a) has all the information. Since the volume flow rate is constant, then ##\frac {dV}{dt}## is a constant.
##\frac {dr}{dt}## is variable.
If you rearrange the expression to solve for ##\frac {dr}{dt}## and you get the answer to (b) and the behavior that explains (c).
The answer (a) has all the information. Since the volume flow rate is constant, then ##\frac {dV}{dt}## is a constant.
##\frac {dr}{dt}## is variable.
If you rearrange the expression to solve for ##\frac {dr}{dt}## and you get the answer to (b) and the behavior that explains (c).