It is strongly suggested you sketch out this vector problem before attempting to answer. A force F1=315N acts in the first quadrant at an angle of 70° above the x-
axis, while a second force F2 = 210N acts in the 3rd quadrant at an angle of
40° below the x-axis.
What is the magnitude of the Resultant of these two forces ?

c)as speed changes, wavelength and frequency change.

everything changes!

the electric field is a “force field” around a charged object that illustrates the direction the electric force would push an imaginary 

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.