If Brian throws a ball straight at a mirror from 5m away, how far
would the virtual image of the ball travel before ‘hitting' the
actual ball?

5m.

Explanation:

The virtual image of the ball is exactly 5m behind the mirror, and the virtual ball behaves exactly like the real ball except that it is located behind the mirror (and it is not a real ball). The two balls, the real and the virtual, hit each other when they both reach the mirror, and if the real ball travels 5 meters to get to the mirror, so must the virtual ball.

Hence, the virtual ball travels 5 meters before it hits the real ball.

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.

the order for strong to weak forces such as

strong nuclear force → electromegnetic force → weak nuclear force → gravitational force

the fundamental forces are those forces that act between to objects or element to make interactions. there are four types of fundamental forces such as strong and weak nuclear forces (due to protons and electrons), electromagnetic force (due to the motion of electrons) and gravitational force (due to orbital movement of the planet). if these forces are arranged on the basis of their maximum strength then the order is

strong nuclear force → electromegnetic force → weak nuclear force → gravitational force