A ball of mass 0.1 kg, initially at rest, is dropped from height of 1m. Ball hits the ground and bounces off the ground. Upon impact with the ground, the velocity reduces by 20%. The height (in m) to which the ball will rise is _______

Two identical trusses support a load of 100 N as shown in the figure. The length of each truss is 1.0m; cross-sectional area is 200 mm² ; Young’s modulus E = 200GPa. The force in the truss AB (in N) is _____ .

Water $$\left( {\rho = 1000kg/{m^3}} \right)$$ flows through a venturimeter with inlet diameter $$80$$ $$mm$$ and throat diameter $$40$$ $$mm.$$ The inlet and throat gauge pressures are measured to be $$400$$ $$kPa$$ and $$130$$ $$kPa$$ respectively. Assuming the venturimeter to be horizontal and neglecting friction, the inlet velocity (in $$m/s$$) is ___________.

Consider fully developed flow in a circular pipe with negligible entrance length effects. Assuming the mass flow rate, density and friction factor to be constant, if the length of the pipe is doubled and the diameter is halved, the head loss due to friction will increase by a factor of