Aluminum wiring can be used as an alternative to copper wiring. Suppose a 40-ft run of 12-gauge aluminum wire (2.05232 mm in diameter) carrying a 7.0-A current is used in a circuit. How long would it take electrons to travel the length of this run and back? There are 6.03 × 10 28 atoms in 1 m3 of aluminum, with each atom contributing three free electrons to the metal.

Ablock of mass m slides on a horizontal frictionless table with an initial speed v0 . it then compresses a spring of force constant k and is brought to rest. the acceleration of gravity is 9.8 m/s2. how much is the spring compressed x from its natural length? 1) x = v0*sqrt(k/(mg)) 2) x=v0*sqrt(m/k) 3) x=v0*((mk)/g) 4) x=v0*sqrt(k/m) 5) x=v0*(m/kg) 6) x=v0*sqrt((mg)/k) 7) x=(v0)^2/(2g) 8) x=v0*(k/(mg)) 9) x=(v0)^2/(2m) 10) x=v0*((mg)/k)