What is Newton's first law of motion?

An object at rest stays at rest and an object in motion stays in motion with constant velocity unless acted on by a net external force.

What does Newton's second law say?

The net external force on a body equals its mass times its acceleration (F = ma); the acceleration is in the direction of the net force.

What is the difference between speed and velocity?

Speed is how fast an object moves (scalar). Velocity includes speed and direction (vector).

What is work in mechanics and how is it calculated?

Work is the transfer of energy when a force causes displacement; W = F · d cos(theta). If the force is in the direction of motion, W = F d.