Applied Mechanics and Graphic Statics
The necessary condition of equilibrium of a body is:

Algebraic sum of vertical components of all the forces must be zero
Algebraic sum of horizontal components of all the forces must be zero
Algebraic sum of the moments of the forces about a point must be zero
All (A), (B) and (C)

ANSWER DOWNLOAD EXAMIANS APP

Applied Mechanics and Graphic Statics
‘u₁’ and ‘u₂’ are the velocities of approach of two moving bodies in the same direction and their corresponding velocities of separation are ‘v₁’ and ‘v₂’. As per Newton's law of collision of elastic bodies, the coefficient of restitution (e) is given by

e = u₂ - u₁/v₁ - v₂
e = v₁ - v₂/u₂ - u₁
e = v₁ - v₂/u₂ + u₁
e = v₂ - v₁/u₁ - u₂

ANSWER DOWNLOAD EXAMIANS APP