Positive charge Q=5 nC is placed on a conducting spherical shell with inner radius R1=20 cm and outer radius R2=30 cm . A particle with charge q=4 nC is placed at the center of the cavity. What is the magnitude of the electric field at a point in the cavity, a distance r=12 cm from the center? (Take Coulomb's constant k=9x10 9 N m2 /C2)

What property is a characteristic of a substance that can be observed and does not change the identity of the substance

Next a skier is pulled by a tow rope up a frictionless ski slope that makes an angle of 15 with the horizontal. the rope moves parallel to the slope with a constant speed of 0.69 m/s. the force of the rope does 800 3 of work on the skier as the skier moves a distance of 8.4 m up the incline. (a) if the rope moved with a constant speed of 2.2 m/s how much work would the force of the rope do on the skier as the skler moved a distance of 8.4 m up the incline? at what rate is the force of the rope doing work on the skier when the rope moves with a speed of (b) 0.69 m/s and (c) 2.2 m/s?

Large electric fields in cell membranes cause ions to move through the cell wall. the field strength in a typical membrane is 1.0 x 10 7 n/c. what is the magnitude of the force on a calcium ion with charge +e? what is its acceleration? is it possible for a particle with the same charge as as calcium to have a different acceleration if placed at this location? what would change the acceleration: mass of the particle? diameter of the particle?