there are four springs stretched by the same mass. spring a stretches 25 cm. spring b stretches
10 cm. spring c stretches 100 cm. spring d stretches 1 cm.
which spring has the smallest spring constant?
а
b
c
d

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 a system with two masses that are moving away from each other. why will the kinetic energy differ if the frame of reference is a stationary observer or one of the masses?

Which system of units is used by only a small number of countries in the world, including the u. s.