Alight-year is the distance light travels in one year, at a speed = 2.998 x 10^8 m/s.

(a) how many meters are there in 1.00 light years?
(b) an au is the average distance from the sun to the earth, 1.50 x 10^8 how many au are there in 1.00 light-year?
(c) what is the speed of light in au/h?

When you push downward on a book at rest on a table, you feel an upward force. does this force depend on friction? defend your answer.

Determine the change in width a, height b, thickness t when a plate is subjected to the uniform distributed load and is made of material having modulus of elasticity e=230 gpa and poisson's ratio ν=1/3. given : a=400 mm and b= 300 mm also the uniformly distributed load in downward y direction of plate is 2 mn/m and in the positive x direction is 3 mn/m and t=20 mm

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.