A particle moves along a circle of radius $$\left( {{{20} \over \pi }} \right)$$ m with constants tangential acceleration. If the velocity of vthe particle is 80 m/s at the end of the second revoluation after motion has begun, the tangential acceleration is

A particle A is dropped from a height and another particle B is projected in horizontal direction with speed of 5/sec from the same height then correct statement is

An object of mass 3 kg is at rest. Now a force of $$\overrightarrow F $$ = 6t² $$\widehat i$$ + 4t $$\widehat j$$ is applied on the object then velocity of object at t = 3 sec. is

If $$\left| {\overrightarrow A + \overrightarrow B } \right| = \left| {\overrightarrow A } \right| + \left| {\overrightarrow B } \right|$$ then angle between A and B will be