David is 5 years younger than his brother Jacob. Jacob is twice as old as their sister Claire.
1. Select all expressions that represent the sum of their ages.
d - 5 + + 20
¢ + 2e + -5)
2e + I + (-5)
U-5) +/+
4 + ( + 5) + (+5)

Athin nonconducting rod with a uniform distribution of positive charge q is bent into a circle of radius r. the central perpendicular axis through the ring is a z-axis, with the origin at the center of the ring. a) what is the magnitude of the electric field due to the rod at z = 0? n/c (b) what is the magnitude of the electric field due to the rod at z = infinity? n/c (c) in terms of r, at what positive value of z is that magnitude maximum? r (d) if r = 4.00 cm and q = 9.00 µc, what is the maximum magnitude? n/c

Is a copper wire a conductor or insulator?

For two variables in a direct proportion, what is the result of doubling one variable?