Two identical balls A and B having velocities of 0.5 m s^$$-$$1 and $$-$$0.3 m s^$$-$$1 respectively collide elastically in one dimension. The velocities of B and A after the collision respectively will be

A particle moves from a point $$\left( { - 2\widehat i + 5\widehat j} \right)$$ to $$\left( {4\widehat j + 3\widehat k} \right)$$ when a force of $$\left( {4\widehat i + 3\widehat j} \right)$$ N is applied. How much work has been done by the force ?

A particle of mass 10 g moves along a circle of radius 6.4 cm with a constant tangential acceleration. What is the magnitude of this acceleration if the kinetic enegy of the particle becomes equal to 8 $$ \times $$ 10^$$-$$4 J by the end of the second revoluation after the beginning of the motion ?

A body of mass 1 kg begins to move under the action of a time dependent force $$\overrightarrow F = \left( {2t\widehat i + 3{t^2}\widehat J} \right)N,$$ where $${\widehat i}$$ and $${\widehat j}$$ are unit vectors along x and y axis. What power will be developed by the force at the time t ?