Neutrons have a proper half-life of 610 seconds. it has been theorized that extremely energetic neutrons could be produced by collisions of ultra-energetic protons (accelerated by an unknown mechanism) with nuclei. for a collection of neutrons to reach earth with 50% surviving, how close to the speed of light must their velocity be (i. e., what is c – v in m/s) if they are created near sagittarius a (black hole at the center of our galaxy), 25,000 light-years distant?

hint: the γ factor is extremely large so use an approximation of β for large γ

An ideal otto cycle has a compression ratio of 10.5, takes in air at 90 kpa and 40°c, and is repeated 2500 times per minute. using constant specific heats at room temperature, determine the thermal efficiency of this cycle and the rate of heat input if the cycle is to produce 90 kw of power.

4r-134a enters the condenser of a residential heat pump at 800 kpa and 50°c at a rate of 0.022 kg/s and leaves at 750 kpa subcooled by 3°c. the refrigerant enters the compressor at 200 kpa superheated by 4°c determine (a) the isentropic efficiency of the compressor, (b) the rate of heat supplied to the heated room, and (c) the cop of the heat pump. also, determine (d) the cop and rate of heat supplied to the heated room if this heat pump operated on the ideal vapor-compression cycle between the pressure limits of 200 and 800 kpa. (0.757, 4.37 kw, 5.12, 6.18, 3.91 kw)

How many meters will a car travel if its speed is 45 m/s in an interval of 11 seconds? question 2 options: a) 450 meters b) 495 meters c) 4.09 meters d) 498 meters