Laplace transform of $$\cos \,\left( {\omega t} \right)$$ is $${s \over {{s^2} + {\omega ^2}.}}$$. The Laplace transform of $${e^{ - 2t}}\,\cos \left( {4t} \right)$$ is

In a statically determinate plane truss, the number of joints $$(j)$$ and the number of members $$(m)$$ are related by

For the truss shown in the figure, the forces F₁ and F₂ are 9 kN and 3 kN, respectively. The force (in kN) in the member QS is

A uniform slender rod (8 m length and 3 kg mass) rotates in a vertical plane about a horizontal axis 1m from its end as shown in the figure. The magnitude of the angular acceleration (in rad/s² ) of the rod at the position shown is _______