một mạch điện kín gồm nguồn điện có suất điện động E=6V và điện trở trong r=1 ôm , mạch ngoài là một điện trở thuần R. biết hiệu suất của nguoonf điện là 75 phần trăm . Gía trị của điện trở R là :

Aboat radioed a distress call to a coast guard station. at the time of the call, a vector a from the station to the boat had a magnitude of 45.0 km and was directed 15.0° east of north. a vector from the station to the point where the boat was later found is = 30.0 km, 15.0° north of east. what are the components of the vector from the point where the distress call was made to point where the boat was found? in other words, what are the components of vector c = b - a?

The heliocentric and the geocentric models of the solar system included these central principles

During the experiment if you could triple the breakaway magnetic force with all other quantities left unchanged, what is the new value for the critical velocity if it was v0 (initial velocity), initially? (b) now if you halved the radius with all other quantities left unchanged, what is the new critical velocity if it was v0 (initial velocity), initially? (c) if during the experiment, critical velocity quadrupled with all other quantities left unchanged, what is the new breakaway force if its magnitude was initially f0,?