A circular balloon is inflated with air flowing at a rate of 10cm3/s. How fast is the radius of the

Discussion in 'Calculator Requests' started by math_celebrity, Mar 23, 2020.

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  1. math_celebrity

    math_celebrity Administrator Staff Member

    A circular balloon is inflated with air flowing at a rate of 10cm3/s. How fast is the radius of the ballon increasing when the radius is 2cm?

    The volume (V) of the balloon with radius (r) is:
    V = 4/3πr^3

    Differentiating with respect to t, we get:
    dV/dt = 4/3π * 3r^2 * dr/dt
    dV/dt = 4πr^2 * dr/dt

    The rate of change of the volume is:
    dV/dt = 10cm^3s^−1

    So, we find dr/dt:
    dr/dt = 1/4πr^2 * dV/dt
    dr/dt = 10/4πr^2
    dr/dt = 5/2πr^2

    Therefore, dr/dt(2cm) is:
    dr/dt(2cm) = 5/2π(2)^2
    dr/dt(2cm) = 5/2π4
    dr/dt(2cm) = 5π/8
     

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