Calculate the concentration of a sample which the wavelength reading is 60 and standard wave length reading is 80 with concentration of standard as 1 00mg/100ml using the standard concentration of 50 - 70mg/100ml 60 80mg/100ml 70 - 90mg/100ml 80 - 100mg/100ml

As you are trying to move a heavy box of mass m, you realize that it is too heavy for you to lift by yourself. there is no one around to , so you attach an ideal pulley to the box and a massless rope to the ceiling, which you wrap around the pulley. you pull up on the rope to lift the box. use g for the magnitude of the acceleration due to gravity and neglect friction forces. once you have pulled hard enough to start the box moving upward, what is the magnitude f of the upward force you must apply to the rope to start raising the box with constant velocity? express the magnitude of the force in terms of m, the mass of the box.