If you consider collimated red light from a hydrogen discharge lamp falls perpendicularly on to a transmission grating, you can compute the number of lines/cm the grating must have for the red(656.2816 nm)line produced in the second order maximum at an angle of 42ofrom the central axis. Where in terms of angular location from the central axis does the blue(486.1327 nm)line in the third order maximum occur

You are your friend move a new refrigerator into his kitchen. you apply a horizontal force of 252 n in the negative x direction to try and move the 56 kg refrigerator. the coefficient of static friction is 0.61. (a) how much static frictional force does the floor exert on the refrigerator? give both magnitude (in n) and direction. magnitude n direction (b) what maximum force (in n) do you need to apply before the refrigerator starts to move?