A bimetallic strip is made from metals with expansion coefficients a1 and a2 (with a2 > a1). The thickness of each layer is s. At some temperature T0, the bimetallic strip is relaxed and straight.

(a) Show that, at temperature T0 + ΔT, the radius of curvature of the strip is

At T0, the lengths of the two layers are the same. At temperature T0 + ΔT, the layers form circular arcs of radii R and R + s, which subtend the same angle q. Assume a small Δ T so that a ΔT (b) If the layers are made of iron and brass, with s = 0.1 mm, what is R for ΔT = 20.0 °C?

To+ AT