The values of function $$(x)$$ at $$5$$ discrete points are given below:

Using Trapezodial rule with step size of $$0.1,$$ the value of $$\,\int\limits_0^{0.4} {f\left( x \right)\,dx\,\,} $$ is __________.

The initial velocity of an object is $$40$$ $$m/s.$$ The acceleration a of the object is given by the following expression: a$$=-0.1v$$
Where v is the instantaneous velocity of the object. The velocity of the object after $$3$$ seconds will be _______

For the truss shown in the figure, the magnitude of the force (in kN) in the member SR is

A small ball of mass 1 kg moving with a velocity of 12 m/s undergoes a direct central impact with a stationary ball of mass 2 kg. The impact is perfectly elastic. The speed (in m/s) of 2 kg mass ball after the impact will be ____________