A book is lying on a table. What is the angle between the normal reaction acting on the book on the table and the weight of the book?

A boy throws a cricket ball from the boundary to the wicket keeper. If the frictional force due to air $$(f_a )$$ cannot be ignored, the forces acting on the ball at the position X are represented by

When a force F = 17 $$-$$ 2x + 6x$$^2$$N acts on a body of mass 2 kg and displaces it from x = 0 m to x = 8 m, the work done is

A rifle bullet loses $$\left(\frac{1}{25}\right)$$th of its velocity in passing through a plank. The least number of such planks required just to stop the bullet is