An iron rod of mass \(2\,\text{kg}\) and length \(1.5\,\text{m}\) is supplied \(18.4\,\text{kJ}\) of heat. If the specific heat capacity of iron is \(460\,\text{J kg}^{-1}\text{K}^{-1}\) and coefficient of linear expansion is \(1.2 \times 10^{-5}\^\circ\text{C}^{-1}\), then the increase in length of the rod is:
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: