A pair of eyeglass frames is made of epoxy plastic. At room temperature (assume 20 ◦C), the frames have?
A pair of eyeglass frames is made of epoxy plastic. At room temperature (assume 20◦ C), the frames have circular lens holes 1.94 cm in radius. To what temperature must the frames be heated in order to insert lenses 1.95 cm in radius? Assume that the average coefficient of linear expansion for epoxy is 0.00013 (◦C)−1.
Answer in units of ◦C
Answers & Comments
Verified answer
Not too difficult.
Needed clearance = 1 × 10^-2 cm
k = 1.3 × 10^-4/C
1 × 10^-2 ÷ 1.3 × 10^-4/C = .77 × 10^2 = 77C
77C + 20C = 97C