There are two inclined surfaces of equal length $(L)$ and same angle of inclination $45^{\circ}$ with the horizontal. One of them is rough and the other is perfectly smooth. A given body takes 2 times as much time to slide down on rough surface than on the smooth surface. The coefficient of kinetic friction $\left(\mu_k\right)$ between the object and the rough surface is close to
A box of mass $$5 \mathrm{~kg}$$ is pulled by a cord, up along a frictionless plane inclined at $$30^{\circ}$$ with the horizontal. The tension in the cord is $$30 \mathrm{~N}$$. The acceleration of the box is (Take $$g=10 \mathrm{~m} \mathrm{~s}^{-2}$$)
A horizontal force $$10 \mathrm{~N}$$ is applied to a block $$A$$ as shown in figure. The mass of blocks $$A$$ and $$B$$ are $$2 \mathrm{~kg}$$ and 3 $$\mathrm{kg}$$ respectively. The blocks slide over a frictionless surface. The force exerted by block $$A$$ on block $$B$$ is :
A particle moving with uniform speed in a circular path maintains: