A Steel Bar with a Cross-Sectional Area of 1

Multiple Choice

A steel bar with a cross-sectional area of 1.00 × 10^-4 m² is heated to 100°C and then it is clamped at both ends with clamps that are 2.0 m apart. When the bar cools to 20°C what is the force exerted by the bar on the clamps? The coefficient of thermal expansion of steel is
12 × 10^-6 K^-1 and Young's modulus for steel is 20 × 10¹⁰ N/m².

A) 1.9 × 10⁴ N
B) 3.8 × 10⁴ N
C) 1.9 × 10³ N
D) 3.8 × 10³ N
E) 1.9 × 10⁵ N