A block of certain mass is placed on a rough floor. The coefficients of static and kinetic friction between the block and the floor are 0.4 and 0.25 respectively. A constant horizontal force \( F = 20 \, \text{N} \) acts on it so that the velocity of the block varies with time according to the following graph. The mass of the block is nearly (Take \( g = 10 \, \text{m/s}^2 \)): 
The existence of metals often plays an important role in our survival, even if we are unaware of them. Our reliance on metals has been strong since the old industrial era. From buildings to jewelry, we utilize them for everything. But where do we acquire these metals from and how are they made? Let's read the occurrence of metal in more detail.
Metals are found in the earth's crust, and it seems to be a good place to extract them through various processes such as metallurgy. The process of extracting metals from ores is called metallurgy. Mining is the most common method of extracting metals from the earth.
In nature, metals are mostly found in mixed conditions. However, they can also be found in a free state. In its natural state, a native metal is one that can be found in its pure form or as part of an alloy. Most metals are exposed to natural processes such as oxidation and corrosion. As a result, only non-reactive metals such as gold, silver, platinum, and others are discovered in their native or open-free condition. Most metals are obtained as compounds, which must be filtered to remove contaminants before being employed in numerous applications.