As you and a friend are entering a chemistry laboratory at your university, you see a sign that states: danger—radioactive isotopes in use. your friend is an accounting major and has not had any science courses yet. she asks you what a radioactive isotope is and you respond correctly with:

“You know how everything is made of atoms, right? Well, you got different kinds of atoms, Helium, Nitrogen, and so on. This are called elements.  Every atom of the same element has the same numbers of protons. Every Carbon atom in the world has 6 protons. But, sometimes, the elements has different numbers of neutrons.So, you could find Carbon with 5 neutrons, or 6, or 7. We called every “flavor” of Carbon an Isotope. And this is what isotopes are. “Flavors” of the elements, with different numbers of neutrons.

Sometimes a particular isotope goes by a transformation, and gives another isotope, of the same,or another, element. When the isotope does that, radiates energy, that can be harmful for humans. We call this isotopes radioactive, so, we places signs to alert other ones when they are present."

reserve is the answer

weight of the box is given as

here this is placed on the inclined of angle 42 degree

now this weight will have two components one is along the incline other is perpendicular to it

so here we need to apply a force parallel to incline opposite to its component of weight

so here the component of weight is given as

here we have

so it requires 75 n force to move it upwards