Two springs A and B having spring constant K_A and K_B (K_A = 2K_B) are stretched by applying force of equal magnitude. If energy stored in spring A is E_A then energy stored in B will be

If $$\overrightarrow F = \left( {60\widehat i + 15\widehat j - 3\widehat k} \right)$$ N and $$\overrightarrow v = \left( {2\widehat i - 4\widehat j + 5\widehat k} \right)$$ m/s, then instantaneous power is

A mass of 1 kg is thrown up with a velocity of 100 m/s. After 5 seconds, it explodes into two parts. One part of mass 400 g comes down with a velocity 25 m/s. The velocity of other part is (Take g = 10 ms^$$-$$2)