Answer:
Today, to benefit humankind, radiation is used in medicine, academics, and industry, as well as for generating electricity. In addition, radiation has useful applications in such areas as agriculture, archaeology (carbon dating), space exploration, law enforcement, geology (including mining), and many others.
The direction of friction force is always the opposite of the direction of the movement.
In this problem, we have an applied force of 20N and this creates a movement. Then, the friction comes in and applies a force of 2.4N.
Because they are in different directions, we need to subtract them:

We don't know the direction because there is no picture (at least I can't see ☺️). But the movement will be to the direction of the 20N.
Oganesson has the highest atomic number and highest atomic mass of all know elements.
Aluminum foil (I think, it may not be right)