Cosmic ray muons are produced high in the atmosphere (at 8000 m say) and travel toward the earth at very nearly the speed of light (0.998c, say). a given the lifetime of the muon (2.2 x 10-6s) how far would it go before disintegrating, according to pre-relativistic physics? would the muons make it to ground level? b now answer the same question using relativistic physics. (because of time dilation the muons last longer, so they travel farther.) c pions are also produced in the upper atmosphere. in fact, the sequence is proton (from outer space) hits proton (in atmosphere): p+p+pions. the pions then decay into muons: 1 + u +vu; nt + ut + vy. but, the lifetime of the pion is much shorter (2.6 x 10-8s). assuming the pions have the same speed (0.998c) will they reach ground level?

Aroll in a paper machine is powered by a separately excited dc machine. operating point 1 (under load): the roll typically operates at 764 rpm and must provide 301 nm of torque to oppose the load of the paper. the armature voltage is 230v for this operating point operating point 2 (no load): when the load is removed the speed of the roll increases to 900 rpm (the field characteristics are unchanged) la ea dev m (a) calculate the maximum torque (units of nm) that the motor can supply with this applied voltage (b) calculate the value of the armature resistance, ra (in ohms) (c) at operating point 1 (loaded condition), the field current, i, and the total input power (armature field), are measured to be to be 10 a and 28,600 w respectively. use this information to calculate the value of the field resistance, rf (in ohms). (d) (d) at operating point 1 (loaded condition), calculate the motor efficiency. express your answer as a percent to at least 2 significant digits. (d) if the field voltage is reduced by 1/2, calculate the new stall torque (in nm) of the motor (f). if the field voltage is reduced by 1/2, calculate the new no-load speed (in rad/sec)

The discovery that the universe appears to be expanding led to a widely accepted theory called a.) the big bang theory b.) the doppler effect c.) hubble’s law d.) solar nebular theory e.) the seyfert theory

This is important 1. what happens to the speed of molecules in water vapor when it condenses to form a liquid? (2 points) the molecules slow down. the molecules speed up. the molecules slow down and then speed up. the molecules speed up and then slow down. 2. how might human activities change to compensate for a decrease in water supplies? (2 points) humans might build a factory. humans might build drainage systems. humans might extract more water from the ground. human behavior does not change because of the water cycle. i'll be grateful if anyone can answer these 2 questions !