The current in some dc circuits decays according to the function i=i0e−t/τ, where i is the current at some point in time, i0 is the initial current at time t=0, and τ is the time constant determined by the properties of the circuit. if you start such a circuit with an initial current of 1.2 amps, and find that after 3.5 seconds have passed it has a current of 0.2 amps, what is the value of the time constant τ for this particular circuit?

Acar drives toward the right over the top of a hill, as shown below. which arrow represents the centripetal acceleration? w x y z

Asheet of steel 1.5 mm thick has nitrogen atmospheres on both sides at 1200oc and is permitted to achieve a steady-state diffusion condition. the diffusion coefficient for nitrogen in steel at this temperature is 6 x 10- 11 m2 /s, and the diffusion flux is found to be 1.2 x 10-7 kg/m2 -s. also, it is known that the concentration of nitrogen in the steel at the high-pressure surface is 4 kg/m3 . how far into the sheet from this high-pressure side will the concentration be 2.0 kg/m3 ? assume a linear concentration profile.

The energy released by a nuclear fusion reaction is produced when