PHYSICS

• Collision is an interaction between two or more bodies that come in contact with each other.
• Momentum is always conserved in all types of collision. However, the total kinetic energy may or may not be conserved, depending on the type of collision.
• Coefficient of restitution is the negative ratio of the relative velocity of two colliding bodies after collision to the relative velocity before collision.
• Elastic collision is where bodies separate after colliding with each other. Both momentum and kinetic energy are conserved during an elastic collision. The coefficient of restitution is equal to 1.
• Inelastic collision is where momentum is conserved but not the kinetic energy.
• If the interacting bodies stick together and move as one after collision, the collision is said to be perfectly inelastic.
• Rotation refers to the motion of a body turning about an axis, where each particle of the body moves along a circular path.
• Angular velocity is the rate at which angular displacement changes with time.
• Angular velocity may be expressed in deg/s, rev/s, or radian/s.
• Moment of inertia, also known as rotational inertia, is the rotational analog for mass and is represented by a capital letter I.
• Moment of inertia is defined as the property of a rotating body to resists change in its state of rotation.
• The larger the moment of inertia, the greater the resistance it offers to angular acceleration.
• The SI unit for moment of inertia is kg • m2
• Radius of gyration is the distance from an axis of rotation where the mass of a body may be assumed to be concentrated without altering the moment of inertia of the body about that axis.
• Radius of gyration is analogous to the center of mass.