To determine which metal among the given options has the highest melting point, we need to consider the melting points of each metal:
From the melting points listed above, it is clear that silver (Ag) has the highest melting point at 961.8°C. This is significantly higher than the other metals listed, which are notable for their relatively low melting points.
Therefore, the correct answer is Ag (Silver).
A particle is moving in a straight line. The variation of position $ x $ as a function of time $ t $ is given as:
$ x = t^3 - 6t^2 + 20t + 15 $.
The velocity of the body when its acceleration becomes zero is: