$A$ book is lying on the table. What is the angle between the action of the book on the table and the reaction of the table on the book ............ $^o$

What physical quantity is represented by the area under the force-time graph?

If impulse $I$ varies with time $t$ as $I \text{ (kg m s}^{-1}) = 20 t^2 - 40 t$. The change in momentum is minimum at ........... $s$.

$A$ ball of mass $0.5 \ kg$ is dropped from a height of $40 \ m$. The ball hits the ground and rises to a height of $10 \ m$. The impulse imparted to the ball during its collision with the ground is (Take $g = 9.8 \ m/s^2$)

$A$ ball of mass $3 \ kg$ strikes a wall at an angle of $60^\circ$ with a velocity of $10 \ m/s$ and rebounds at the same angle and speed. What is the change in momentum of the ball in $MKS$ units?

Consider the following statement: When jumping from some height,you should bend your knees as you come to rest,instead of keeping your legs stiff. Which of the following relations can be useful in explaining the statement?