$A$ body whose momentum is constant must have constant

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

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

Two billiard balls of equal mass $30 \, g$ strike a rigid wall with the same speed of $108 \, km/h$ (as shown) but at different angles. If the balls get reflected with the same speed, then the ratio of the magnitude of impulses imparted to ball $'a'$ and ball $'b'$ by the wall along the $'X'$ direction is:

$A$ tennis ball is dropped onto the floor from a height of $9.8\,m$. It rebounds to a height of $5.0\,m$. The ball comes in contact with the floor for $0.2\,s$. The average acceleration during contact is $..........\,m/s^2$. [Given $g = 10\,m/s^2$]

$A$ body of mass $2 \,kg$ collides with a wall with a speed of $100 \,ms^{-1}$ and rebounds with the same speed. If the time of contact is $1/50 \,s$,the force exerted on the wall is