17. A 2.0 microcoulomb particle with a kinetic energy of 0.10 J is fired into a uniform magnetic field of magnitude 0.10 T. If the particle moves in a uniform circular path of radius 3.0 m, determine its mass. (A) 1.3 × 10⁻¹² kg (B) 1.8 × 10⁻¹² kg (C) 3.1 × 10⁻¹² kg (D) 3.7 × 10⁻¹² kg (E) 4.2 × 10⁻¹² kg

10. A copper telephone wire has essentially no sag between poles 35.0 m apart on a winter day when the temperature is -20.0°C. How much longer is the wire on a summer day when Tc = 35.0°C? Assume that the thermal coefficient of copper is constant throughout this range at its room temperature value. The average coefficient of linear expansion for copper is 17 × 10⁻⁶ (°C)⁻¹. (A) 3.27 cm (B) 4.12 cm (C) 1.00 cm (D) 12.04 cm (E) 8.40 cm

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