1.What is the change in internal energy for a piston and cylinder system initally containing 0.5m^3 of helium at 100kPa and 5C being compressed to 200kPa?
(a) -11.5 kJ
(b) 0 kJ
(c) 12.6 kJ
(d) 37.5 kJ
(e) 121.9 kJ
(f) 321.1 kJ
2.The two upper lengths of the welded Y-shaped assembly of uniform slender rods have a mass per unit length of 0.3 kg/m, while the lower length has a mass of 0.7 kg/m. Locate the mass center of the assembly. lenghts of all rods aew 30mm