The velocity-time graph for a body of mass $10\, kg$ is shown in the figure. The work done on the body in the first two seconds of the motion is ................ $J$.

If mechanical work is done on an object,does its kinetic energy increase or decrease?

$A$ body thrown vertically upwards from the ground reaches a maximum height $h$. The ratio of the kinetic and potential energies of the body at a height $40 \%$ of $h$ from the ground is

Select the incorrect statement regarding the mechanical energy of a body/system.

$A$ force of $5\,N$,making an angle $\theta$ with the horizontal,acts on an object and displaces it by $0.4\,m$ along the horizontal direction. If the object gains a kinetic energy of $1\,J$,the horizontal component of the force is......$N$. (in $.5$)

$A$ spring-block system is placed on a rough horizontal floor. The block is pulled towards the right to give the spring an elongation $x$ such that $\frac{\mu mg}{K} < x < \frac{2\mu mg}{K}$,and then released. Which of the following laws/principles of physics can be applied to the spring-block system?