Pirect pressure exerted by a certain liquid at a given point varies directly as the depth of the point beneath the suriace of the liquid. The pressure at 50 feet is 23 pounds per square What is the pressure at 130 feet?

7.2 A beam of light travels from water to plastic. The speed of light in plastic is \( 2,05 \times 10^{8} \mathrm{~m} \cdot \mathrm{~s}^{-1} \). The refractive index of water is 1,33 . Calculate the refractive index of plastic.

QUESTION 6 (Start on a new page.) It has been established that the planet Omega has a moon and that the moon of Omega orbits the planet at a height, above the surface of Omega, which is equal to twice the radius of Omega. The mass of planet Omega is \( 3 \times 10^{15} \mathrm{~kg} \) and the mass of its moon is \( 1.5 \times 10^{13} \mathrm{~kg} \). The radius of the planet Omega is \( 8.5 \times 10^{6} \mathrm{~m} \) and the radius of its moon is \( 2.5 \times 10^{5} \mathrm{~m} \). 6.1 Determine the distance between the centre of the planet Omega and the centre of its moon.

9. Si dejamos caer al suelo una piedra cuya masa es de 4 kg desde una altura de 4 m , ¿Cuál es la energía cinética cuando ya ha recorrido la mitad de la caída a) hacia el suelo? b) CCual es la velocidad cuando alcanza el suelo?

A coil with an area of \( 0.6 \mathrm{~m}^{2} \) is held with its axis coinciding with the direction of a magnetic field (surface perpendicular to magnetic field), with a strength of 0.4 T . 8.3 Calculate the magnetic flux.

8.4 To produce an emf of 9 V , the area of the coil, with its axis coinciding with the direction of a magnetic field (area perpendicular to magnetic field), is halved in 2 minutes from \( 0.6 \mathrm{~m}^{2} \) to \( 0,3 \mathrm{~m}^{2} \). Calculate the number of turns around the coil.