Work Energy and...

Mass of $$B$$ is four times that of $$A . B$$ moves with a velocity half that of $$A$$. Then, $$B$$ has 

A body of mass $$15\ kg$$ moving with a velocity of $$10\ ms^{-1}$$ is bought to rest. The work done by the brake is

The work done in placing a charge of 8$$\times $$$${ 10 }^{ -18 }$$ coulomb on a condenser of capacity 100 micro-farad is 

A bod of mass M is suspended by a massless string of length L.The horizontal velocity V at position A is just sufficient to make real the point B.The angle $$\theta$$ at which the speed of the bob is half of that it A satisfies:

A body of mass 1 kg begins to move under the action of a time dependent  force $$ \overrightarrow { F } =(2t\hat { i } +3t^{ 2 }\hat { j } ) $$ N, where $$ \hat { i } $$ and $$ \hat { j }  $$ are unit vectors along x and y axes. What power will be developed by the force at the time t?

A particle is moving in a vertical circle. The tension in the string when passing through two positions at angles $${30}^{o}$$ and $${60}^{o}$$ from vertical (lowest position) are $${T}_{1}$$ and $${T}_{2}$$ respectively, then

A body of mass $$2\ kg$$ moving under a force has relation between displacement $$x$$ and time $$t$$ as $$x=\dfrac{t^{3}}{3}$$ where $$x$$ is in metre and $$t$$ is in sec. The work done by the body in first two second will be

Work done by a force $$\vec{F}=(\hat{i}+2\hat{j}+3\hat{k})\ N$$ action on a particle in displacing it from the point $$\vec{r}_{1}=\hat{i}+\hat{j}+\hat{k}$$ to the point $$\vec{r}_{1}=\hat{i}-\hat{j}-2\hat{k}$$

By applying a force $$F=(3xy-5z) j +4zk$$ a particle is moved along the path $$y=x^2$$ from point $$(0,0,0)$$ to the point $$(2,4,0)$$. The work done by the F on the particle is (all values are in SI units)

Two masses $$10 \ gm$$ and $$40 \ gm$$ are moving with kinetic energies in the ratio $$9:25$$. The ratio of their linear momentum is: