Correct answer: Pyrolusite
Explanation:
Pyrolusite is a mineral that contains manganese dioxide (MnO₂). It is one of the most important ores of manganese.
Here’s what the other minerals contain:
- Galena – Lead sulfide (PbS)
- Cinnabar – Mercury sulfide (HgS)
- Horn silver – Silver chloride (AgCl)
A force of \( P = 100 \, {N} \) is applied at the ends of the pliers as shown in the figure. Neglecting friction, the force exerted by the upper jaw on the workpiece is ........... N (in integer).
Consider a beam with a square box cross-section as shown in the figure. The outer square has a length of 10 mm. The thickness of the section is 1 mm. The area moment of inertia about the x-axis is ........... mm\(^4\) (in integer). 