Most binary systems with an invisible companion contain a large, bright star and a small, dim star hidden by the light of its larger companion. however, in some binary systems, the unseen companion may be a black hole instead of a small star. one of the most likely black hole candidates in a binary system is an object called cygnus x-1. if you were an astronomer trying to prove that cygnus x-1 is a black hole, which of the following observations would provide evidence in support of your claim? check all that applya. cygnus x-1 has a mass one-tenth that of the sun. b. cygnus x-1 produces a large amount of x-ray emissions. c. cygnus x-1 produces no x-ray emissions. d. cygnus x-1 has a diameter less than 300 kilometers. e. cygnus x-1 has a mass of 10 solar masses. f. cygnus x-1 has a diameter much greater than 300 kilometers.

1. consider the case in which air fills air shocks on a truck trailer. the pressure in the shocks is 2 mpa. the temperature is 300 k. the diameter of the shock piston is 10 cm and the initial length of the cylindrical cavity containing the compressed air is 40 cm. a. the truck is gradually loaded over a period of a day in a static setting. the temperature is held constant for the atmosphere and thus for the gas shock. calculate the compressibility of the air in the shock for this condition when the truck is initially being loaded. b. if the shocks were loaded in a dynamic setting by driving over bumps, what would be the compressibility? state your assumption. c. what is the initial load on the shock if the shock is in an atmospheric 100 kpa? d. if the shock is compressed using the process described in part a, and the air shock compressed air cavity length decreases to 20 cm, what is the additional load applied to the shock?

Matter is needed to transfer thermal energy bya. conductionb. convectionc. radiation d. both a & b.

Slab pull” is a type of tectonic plate movement that occurs due to the forces of mantle convection and results in the subduction of the lithosphere true or false