Please help Im taking a test and I need to pass a charged partical will create an electric field around itself, how do you find the direction of the field lines

1) the lines are drawn from the electron to the proton
2) the lines are drawn from negative to positive points
3) the lines are drawn in a direction that a positive test charge will move
4) the lines are drawn in a direction that a positive test charge

You are about to open a container of soy milk but notice that there are instructions to “shake well before serving.” the soy milk is most likely a

The ultracentrifuge is an important tool for separating and analyzing proteins. because of the enormous centripetal accelerations, the centrifuge must be carefully balanced, with each sample matched by a sample of identical mass on the opposite side. any difference in the masses of opposing samples creates a net force on the shaft of the rotor, potentially leading to a catastrophic failure of the apparatus. suppose a scientist makes a slight error in sample preparation and one sample has a mass 10 mg larger than the opposing sample. if the samples are 12 cm from the axis of the rotor and the ultracentrifuge spins at 70,000 rpm, what is the magnitude of the net force on the rotor due to the unbalanced samples? ( be thorough on your answer)

Awave with a frequency of 500 hz is traveling at a speed of 100 m/s.what is the wavelength?