What is the basic definition of a black hole?
a. any compact mass that emits no light
b. a dead star that has faded from view any object from which the escape velocity exceeds
c. the speed of light any object made from dark matter
d. a dead galactic nucleus that can only be viewed in infrared

What is a neurotransmitter involved in mood reward, addiction, and motor behaviors?

Wo small variable-thrust jets are actuated to keep the spacecraft angular velocity about the z-axis constant at ? 0 = 1.16 rad/s as the two telescoping booms are extended from r1 = 1.18 m to r2 = 4.69 m at a constant rate over a period of 124 seconds. the small 19-kg experiment modules at the ends of the booms may be treated as particles, and the mass of the rigid booms is negligible. determine the necessary thrust t for each jet as a function of time where t = 0 is the time when the telescoping action is begun. after you have the general expression for t, answer the questions. show work.

2. which of the following devices is associated with the reception of radio signals? o a. demodulator o b. transmitting antenna o c. oscillator o d. microphone