Work Energy and...

A force $$F=(3{x}^{2}+2x-7)N$$ acts on a $$2kg$$ body as a result of which the body gets displaced from $$x=0$$ to $$x=5m$$. The work done by the force will be:

A position dependent force F = $$3x^{2} - 2x + 7$$ acts on a body of mass 7 kg and displace it from $$x$$ = 10 m to $$x$$ = 5 m. The work done on the body is $$x'$$ joule. If both $$F$$ and $$x'$$ are measured in SI units, the value of $$x'$$ is :

Two springs $$A$$ and $$B(k_{A}=2 k_{B})$$ are stretched by a applying forces of equal magnitudes at the four ends. If the energy stored in $$A$$ is $$E$$, that in $$B$$ is

A particle moves along the $$x-$$axis from $$x=0$$ to $$x=5m$$ under the influence of a force given by $$F=$$$$7 - 2x + 3{x^2}N$$. The work done in the process is

A circular coil of radius 4 cm has 50 turns. In this coil a current of 2 A is flowing. It is placed in a magnetic field of $$0.1 \ weber / m^2$$. the moment of work done in rotating it through $$180^\circ$$ from its equilibrium position will be

A string of length $$L$$ and force constant $$K$$ is stretched to obtain extension $$l$$. It is further stretched to obtain extension $${l}_{1}$$.The work done in second stretching is

A boy is swinging on a swing such that his lowest and highest positions are at heights of $$2m$$ and $$4.5m$$ respectively. His velocity at the lowest position is:

In the figure, a 4.0 kg ball is on the end of a 1.6 m rope that is fixed at O. The ball is held at point A, with the rope horizontal is given an initial downward velocity. The ball moves theough three qyarters of a circle with no friction and arrives at B, with the rope barely under tension. Thee initial velocity of the ball, at point A, is closest to

A body mass of $$ 6kg $$ is under a force which causes displacement in it given by$$ = \dfrac{{{t^2}}}{4}$$  metres where $$t$$ is time.The work done by the force in $$2$$ seconds is 

The velocity $$(v)$$ of a particle of mass $$m$$ moving along x-axis is given by $$v = \alpha \sqrt {x}$$, where $$\alpha$$ is a constant. Find work done by force acting on particle during its motion from $$x = 0$$ to $$x = 2m$$.