A solenoid used to produce magnetic fields for research purposes is 1.7 m long, with an inner radius of 29 cm and 1300 turns of wire. When running, the solenoid produced a field of 1.1 T in the center.

the only real purpose of sputnik 1 was to beat the us into space. we were getting close to launching a useful satellite, explorer 1 - which launched on january 31, 1958. the ussr had to beat that, so they launched sputnik 1 on october 4, 19

305.7

explanation:

density =m/v

density =917/3.00

density = 305.

approximately = 305.7

in four significant figures