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                                       Water - Cement Ratio & Gel – Space Ratio. Abrams' law (also called Abrams' water-cement ratio law) is a concept in civil engineering. The law states the strength of a concrete mix is inversely related to the mass ratio of water to cement. As the water content increases, the strength of concrete decreases. What is the difference between the water-cement ratio and the gel space ratio?  The gel/space ratio is the ratio of the solid products of hydration to the space available for these hydration products. ...  A higher water/cement ratio decreases the gel/space ratio increasing the porosity thereby decreases the strength of concrete. What is the maturity of concrete? Concrete maturity is an index value that represents the progression of concrete curing. It is based on an equation that takes into account concrete temperature, time, and strength gain. Concrete maturity is an accurate way to determine real-time strength values of curing

                                    DRAG ON SPHERE & TERMINAL VELOCITY The drag of a Sphere. The aerodynamic drag on an object depends on several factors, including the shape, size, inclination, and flow conditions. ... Where D is equal to the drag, rho is the air density, V is the velocity, A is a reference area, and Cd is the drag coefficient. Terminal velocity is the maximum velocity attainable by an object as it falls through a fluid (air is the most common example). It occurs when the sum of the drag force (Fd) and the buoyancy is equal to the downward force of gravity (FG) acting on the object. Since the net force on the object is zero, the object has zero acceleration Most useful and reliable A textbook of fluid mechanics by Dr. RK Bansal is available at https://amzn.to/3keCpcZ Video link https://youtu.be/P-s5ggi_aCU