As a part of producing MOSFET transistors, a p-type silicon (Si) wafer containing boron (B) dopants at a concentration of 1x1019 atoms/cm3 is being processed to create a PN junction by doping the wafer with phosphorous (P) atoms using a P-producing gas. Assume that the wafer does not contain P prior to the diffusion process. The solubility of P in Si at 1000°C is 1x1020 atoms/cm3. It is determined that the PN junction depth of 1 um was produced after 60 minutes at 1000°C. The activation energy for estimating the diffusion coefficient of P in Si is 2.5x105 J/mole. Based on this result, estimate the pre-exponential constant for the diffusion coefficient of P in Si at 1000°C in cm2/s.

Acatapult is tested by roman legionnaires. they tabulate the results in a papyrus and 2000 years later the archaeological team reads (distances translated into modern units): range = 0.4 km; angle of launch = π/5 rad; landing height = launch height. what is the initial velocity of launch of the boulders if air resistance is negligible?

The 20@kg wheel has a radius of gyration about its center g of kg = 300 mm. when it is subjected to a couple moment of m = 50 n # m, it rolls without slipping. determine the angular velocity of the wheel after its mass center g has traveled through a distance of sg = 20 m, starting from rest.

Three different objects, all with different masses, are initially at rest at the bottom of a set of steps. each step is of uniform height . the mass of each object is a multiple of the base mass : object 1 has mass 4..00m , object 2 has mass 1..96m , and object 3 has mass . when the objects are at the bottom of the steps, define the total gravitational potential energy of the three-object system to be zero. if the objects are then relocated as shown, what is the new total potential energy of the system? each answer requires the numerical coefficient to an algebraic expression. each algebraic expression is given using some combination of the variables , , and , where is the acceleration due to gravity. enter only the numerical coefficient. (example: if the answer is 1..23mgd , just enter 1.23)