What physical properties of nylon and leather make them good for materials to use for shoelaces

You have been called to testify as an expert witness in a trial involving a head-on collision. car a weighs 1515 lb and was traveling eastward. car b weighs 1125 lb and was traveling westward at 44.0 mph. the cars locked bumpers and slid eastward with their wheels locked for 22.5 ft before stopping. you have measured the coefficient of kinetic friction between the tires and the pavement to be 0.750 . how fast (in miles per hour) was car a traveling just before the collision? (this problem uses english units because they would be used in a u.s. legal proceeding.)

What type of light does this light bulb produce most (i.e. at what wavelength does the spectrum have maximum intensity)?

Which transition by an electron will release the greatest amount of energy? oa ob oc od