1.A runner has a displacement of 20 meters in 5 seconds, what is his velocity
during this time?

The required velocity of runner is 4m/s.

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.

spare some change and give it to the poor

explanation:

plz : ((