A child is sitting on a swing. Its minimum and maximum heights from the ground 0.75 m and 2 m respectively, its maximum speed will be

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)

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