The displacement-time graph of a particle moving in a straight line is as shown in the figure. Select the correct alternative.

State the principle of conservation of mechanical energy for a conservative force.

$A$ 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 $(g = 10 \, m/s^2)$.

$A$ closed circular tube of average radius $15\,cm$,whose inner walls are rough,is kept in a vertical plane. $A$ block of mass $1\,kg$ just fits inside the tube. The speed of the block is $22\,m/s$ when it is introduced at the top of the tube. After completing five oscillations,the block stops at the bottom region of the tube. The work done by the tube on the block is $......J$. [Given $g=10\,m/s^2$]

$A$ body of mass $m$ is travelling with a velocity $u$. When a constant retarding force $F$ is applied,it comes to rest after travelling a distance $s_{1}$. If the initial velocity is $2u$,with the same force $F$,the distance travelled before it comes to rest is $s_{2}$. Then,

$A$ sphere is suspended by a thread of length $\ell$. What minimum horizontal velocity has to be imparted to the sphere for it to reach the height of the suspension point?