$A$ particle is placed at the point $A$ of a frictionless track $ABC$ as shown in the figure. It is gently pushed toward the right. The speed of the particle when it reaches the point $B$ is: (Take $g = 10 \ m/s^2$).

$A$ particle of mass $m$ moves on a straight line with its velocity increasing with distance according to the equation $v = \alpha \sqrt{x}$,where $\alpha$ is a constant. The total work done by all the forces applied on the particle during its displacement from $x = 0$ to $x = d$ will be:

The work-energy theorem is valid in the presence of:

$A$ cricket ball of mass $0.15 \, kg$ is thrown vertically up by a bowling machine so that it rises to a maximum height of $20 \, m$ after leaving the machine. If the part pushing the ball applies a constant force $F$ on the ball and moves a distance of $0.2 \, m$ while launching the ball,the value of $F$ (in $N$) is $(g = 10 \, m/s^2)$.

$A$ simple pendulum is released from $A$ as shown in the figure. If $m$ and $l$ represent the mass of the bob and the length of the pendulum respectively,the gain in kinetic energy at $B$ is

$A$ vertical spring with force constant $k$ is fixed on a table. $A$ ball of mass $m$ at a height $h$ above the free upper end of the spring falls vertically on the spring so that the spring is compressed by a distance $d$. The net work done in the process is