26. A weight of 20N stretches a spring by 0.5cm. Calculate the extension when the applied weight is 60N.
A. 0.25cm
B.1.5cm C. 2.0cm D. 4.0cm

Which statement best describes the superposition principle? a.) if two in-phase waves arrive simultaneously at a point, their amplitudes add up b.) if two out-of-phase waves arrive simultaneously at a point, their amplitudes add up c.) if two in-phase waves arrive at a point one after another, their amplitudes add up d.) if two out-of-phase waves arrive at a point one after another, their amplitudes adds up