Which of the following is not true of exercise machines?
a.
most exercise machines are expensive to purchase individually.
b.
most exercise machines require spotters for safe operation.
c.
most exercise machines require less skill to use than free weights.
d.
most exercise machines can only be used for a limited number of exercises.

a charge 3q is at the origin, and a charge −2q is on the positive x axis at x=a. part a where on the x-axis would you place a third charge so it would experience no net electric force? enter an expression for the exact answer, which will involve a square-root sign. (do not enter an approximate decimal answer.)

adding a(n) to an electric circuit would increase the magnetic field around a wire;

b. solenoid

a solenoid is a type of electromagnet whose purpose is to generate a controlled magnetic field.

if the purpose of the solenoid is instead to impede changes in the electric current, a solenoid can be more specifically classified as an inductor rather than an electromagnet.