Acertain metal has a coefficient of linear expansion of 2.00 × 10-5 k-1. it has been kept in a laboratory oven at 325°c for a long time. it is now removed from the oven and placed in a freezer at ‐145°c. after it has reached freezer temperature, the percent change in its density during this process is closest to a) +2.90%. b) ‐2.90%. c) +2.74%. d) ‐2.74%. e) it is not possible to tell without knowing the mass and original volume of the metal.

When does your body conduct current more readily?

Two 1.20-m nonconducting wires meet at a right angle. one segment carries + 2.50 µc of charge distributed uniformly along its length, and the other carries - 2.50 µc distributed uniformly along it, as shown in fig. 21.50. ( a. find the magnitude and direction of the electric field these wires produce at point p, which is 60.0 cm from each wire. ( b. if an electron is released at p, what are the magnitude and direction of the net force that these wires exert on it?

Air is contained in a variable-load piston-cylinder device equipped with a paddle wheel. initially, air is at 400 kpa and 17°c. the paddle wheel is now turned by an external electric motor until 75 kj/kg of work has been transferred to air. during this process, heat is transferred to maintain a constant air temperature while allowing the gas volume to triple. calculate the required amount of heat transfer in kj/kg.