$A$ block of mass $2 \ kg$ moves freely along the $x$-axis. It is at rest at $t = 0$. The force $F(t)$ acting on the block varies with time $t$ as shown in the figure. What is the kinetic energy of the block after $4.5 \ s$ (in $J$)?

Action and reaction forces act on

$A$ force is applied to a body of mass $2 \,kg$ at rest on a frictionless horizontal surface, as shown in the force-time $(F-t)$ graph. The speed of the body after $1 \,s$ is: (in $\,m/s$)

In Newtonian mechanics,which parameter is changed by the application of an external force?

$A$ 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:

$A$ ball of mass $m$ moves with speed $v$ and strikes a wall normally and is reflected back normally. If its time of contact with the wall is $t$,find the force exerted by the ball on the wall.