A 10cm×10cm×10cm block of steel ( ρsteel=7900kg/m3 ) is suspended from a spring scale. The scale is in newtons. (a) What is the scale reading if the block is in air? (b) What is the scale reading after the block has been lowered into a beaker of liquid with ρ=700 kg/m3 and is completely submerged?

Will you chech and finish these for me, because i am stumped with them.

With the simplified model of the eye, what corrective lens (specified by focal length as measured in air) would be needed to enable a person underwater to focus an infinitely distant object? (be careful-the focal length of a lens underwater is not the same as in air! assume that the corrective lens has a refractive index of 1.62 and that the lens is used in eyeglasses, not goggles, so there is water on both sides of the lens. assume that the eyeglasses are 1.90

Consider the following position function. find (a) the velocity and the speed of the object and (b) the acceleration of the object. bold r left parenthesis t right parenthesisr(t)equals=left angle 6 t superscript 4 baseline comma 2 t cubed right angle6t4,2t3 for tgreater than or equals≥0