2. Dynamics
Newton's laws of motion are three physical laws that, together, laid the foundation for classical mechanics.
In an inertial frame of reference, an object either remains at rest or continues to move at a constant velocity, unless acted upon by a force.
In an inertial frame of reference, the vector sum of the forces F on an object is equal to the mass m of that object multiplied by the acceleration a of the object: F = ma.
When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction on the first body.
Work, Power and Energy is a very important concept in physics. Work done by all the forces is equal to the change in kinetic energy.
In physics, work is related to the amount of energy transferred in or from a system by a force. It is a scalar-valued quantity with SI units of Joule.
Work can be represented in a number of ways. For the case where a body is moving in a steady direction, the work done by a constant force F acting parallel to the displacement is defined as
The dot product of force and displacement is known as work.
When the force is not acting parallel to the body's direction of movement, the work done is defined as a dot product of the force and the displacement,
Power is defined to be the rate at which work is performed, or the derivative of work over time. The SI unit for power is the watt. OR: Rate of doing work with respect to time is called power:
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Energy is stored work. It has the same units as work, the Joule (J).
There are two basic forms of energy. Potential energy and kinetic energy.
Gravitational potential energy: a mass (m) has been lifted to a height (h); when released it will be pulled down by gravity (g) and can do work on another object as it falls.
Elastic potential energy: work has been done on a elastic body to compress or stretch it; for example the spring, it has the ability to push or pull on another object and do work on it.
Kinetic energy: A mass (m) is moving (v) and can do work when it hits another object.