When a thin washer has outer radius

MATHEMATICS · Single correct · AP · Calculus AB · Applications of Integration · Applications of Integration

Problem

R

, inner radius

r

(R>r)

, and thickness

dx

measured along the

x

-axis, which of the following gives the differential volume

dV

of the washer? (a)

dV=\pi\bigl(R-r\bigr)^{2}\,dx

(b)

dV=2\pi\bigl(R^{2}-r^{2}\bigr)\,dx

(c)

dV=\pi\bigl(R^{2}-r^{2}\bigr)\,dx

(d)

dV=\pi\bigl(R^{2}+r^{2}\bigr)\,dx