A closed vessel contains 0.1 mole of a monoatomic ideal gas at 200 K. If 0.05 mole of the same gas at 400 K is added to it, the final equilibrium temperature (in K) of the gas in the vessel will be close to _______.

Starting from the origin at time t = 0, with initial velocity 5$$\widehat j$$ ms^-1 , a particle moves in the x-y plane with a constant acceleration of $$\left( {10\widehat i + 4\widehat j} \right)$$ ms^-2. At time t, its coordinates are (20 m, y₀ m). The values of t and y₀ are, respectively: