$A$ 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 ............ $^o$

$A$ batsman deflects a ball by an angle of $45^{\circ}$ without changing its initial speed,which is equal to $54 \; km/h$. What is the impulse imparted to the ball in $kg \; m/s$? (Mass of the ball is $0.15 \; kg$.)

$A$ block of mass $2 \ kg$ is free to move along the $x$-axis. It is at rest and from $t=0$ onwards it is subjected to a time-dependent force $F(t)$ in the $x$ direction. The force $F(t)$ varies with $t$ as shown in the figure. The kinetic energy of the block after $4.5 \ s$ is (in $J$)

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?

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 ........... $s$.

$A$ body whose momentum is constant must have constant