1. a simple pendulum has a 150.0 � mass tied to it and 28.00 seconds are required to complete 10 oscillations. (a) if � = 9.80 �/�@, what is the length of the pendulum? (b) when the mass is released from a certain hight, its speed as it passes through its lowest point is measured to be 1.850 �/�. calculate the tension in the string at the pendulum’s lowest point. (c) the 150.0 � mass is removed from the string forming the pendulum, and it is attached to a spring. if 27.00 seconds is required to complete 25 oscillations on the spring, calculate the spring constant. (d) if you are to move pendulum to another planet where � = 6.78 �/�@, how will period change? (e) if you are to move spring mass system to another planet where � = 6.7

b.transmitters send radio waves, and receivers capture radio waves.

where are the vectors ?

speed of light in vacuum is 300,000 km/s

speed of light in other mediums is given by the expression v = c/n, where c is the speed of light in vacuum and n is the refractive index of medium.

for the first medium v = 200,000 km/s

  so, refractive index of medium = 300000/200000 = 1.5

    1.5 refractive index is usually for glass. so first medium is glass.

for the second medium v = 250,00 km/s

so, refractive index of medium = 300000/250000 = 1.2

    1.2 refractive index is usually for water. so second medium is water.

for the third medium v = 0 km/s

so, refractive index of medium = 300000/0 = ∞

    ∞ refractive index is usually for opaque mediums. so third medium is opaque medium.