$A$ 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 $J$)

$A$ ball hits a vertical wall horizontally at $10 \ m/s$ and bounces back at $10 \ m/s$. Which of the following statements is correct?

$A$ ball of mass $50 \,g$ is dropped from a height of $20 \,m$. $A$ boy on the ground hits the ball vertically upwards with a bat with an average force of $200 \,N$,so that it attains a vertical height of $45 \,m$. The time for which the ball remains in contact with the bat is ........... of a second. [Take $g = 10 \,m/s^2$]

Two objects of different masses have the same momentum. Which of the two objects will be moving faster?

$A$ $140\, g$ 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 $N$)

$A$ ball of mass $m$ moving with velocity $v_0$ collides with a wall as shown in the figure. After impact,it rebounds with a velocity $\frac{3}{4}v_0$. The impulse acting on the ball during the impact is