A block of certain mass is placed on a rough floor. The coefficients of static and kinetic friction between the block and the floor are 0.4 and 0.25 respectively. A constant horizontal force \( F = 20 \, \text{N} \) acts on it so that the velocity of the block varies with time according to the following graph. The mass of the block is nearly (Take \( g = 10 \, \text{m/s}^2 \)): 
All reactants need to overcome certain energy, better known as activation energy in order to form products. This activation energy is the difference between the energy of the transition state and the reactant species.
Catalysis of chemical reactions is generally divided into two categories: