$A$ 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?

$A$ ball of mass $3 \ kg$,moving with a speed of $100 \ m/s$,strikes a wall at an angle of $60^{\circ}$ with the wall (as shown in the figure). The ball rebounds at the same speed and remains in contact with the wall for $0.2 \ s$. The force exerted by the ball on the wall is:

$A$ machine gun fires a bullet of mass $40\,g$ with a velocity $1200\,m/s$. The man holding it can exert a maximum force of $144\,N$ on the gun. How many bullets can he fire per second at the most?

Two bodies $A$ and $B$ collide as shown in Fig. $(i)$ and $(ii)$. Which statement is true?

$A$ $140\, g$ ball,in horizontal flight with a speed $v_1$ of $39.0\, m/s$,is struck by a bat. After leaving the bat,the ball travels in the opposite direction with speed $v_2 = 39.0\, m/s$. If the impact time $\Delta t$ for the ball-bat collision is $1.20\, ms$,what average net force acts on the ball? (in $N$)

Figures $(a)$,$(b)$,$(c)$ and $(d)$ show the variation of force with time. The impulse is highest in which figure?