12. A 5 kg mass is placed in an elevator that is accelerating upwards at 4 m/s2. The apparent weight of this mass is a. 69 N b. 29 N C. 20 N d. 49 N 13 A wave travels at a speed of 10 cm/s in shallow water. The wavelength of the wave in the shallow water is 2 cm. The speed of the wave in the deep water is 12 cm/s. The wavelength of the wave in deep water is a. 0.6 cm b. 2.4 cm c. 1.7 cm d. 0.42 cm 14. How many changes of state are shown in this heating graph? Temperature .C A Thermal energy a. 4 1 C . 2 d. 3 15. A string is plucked producing four loops (antinodes). The length of the string is 12 m. The wavelength of the wave must be a. 6 m b. 3 m c. 48 m d. 24 m 16. A scientist is performing an extended experiment and has a sample of 25.0 g of Cobalt-60, which has a half-life of 5.27 years. How much of the sample is left after 2.00 years? a. 18.2 g b. 19.2 g c. 20.8 g d. 19.9 g