
Patrick B. answered 10/18/20
Math and computer tutor/teacher
V = (4/3) PI * R^3
dV/dt = 4 PI R^2 * dR/dt
4.9 = 4 * pi * (1.5)^2 * dr/dt
4.9 / [ 4 * pi * 1/.5^2] = dr/dt
Kendra M.
asked 10/17/20A spherical balloon is being inflated by a compressor that is pumping air at a rate of At 4.9ft^3 /min . what rate is the radius of the balloon increasing when the radius is 1.5 ft Round to three decimal places.
Patrick B. answered 10/18/20
Math and computer tutor/teacher
V = (4/3) PI * R^3
dV/dt = 4 PI R^2 * dR/dt
4.9 = 4 * pi * (1.5)^2 * dr/dt
4.9 / [ 4 * pi * 1/.5^2] = dr/dt
Let the rate that the volume increases/decreases be represented by:
dV/dt = 4.9
Your goal is to solve for dr/dt (the rate at which the radius is increasing/decreasing).
Start with the general formula for the volume of a sphere:
V = (4/3)π r 3
Differentiate both sides with respect to t (time).
dV/dt = 4π r 2(dr/dt)
Plug in the information provided in the question, dV/dt = 4.9 and r = 1.5.
4.9 = 4π (1.5)2 (dr/dt)
Solve for the expression dr/dt, which represents the rate the radius is changing.
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