Key points on mechanics

MECHANICS

My name is Science Lair ,i would take you through some useful aspects in mechanics
Lets start with displacement

Displacement 

Displacement is total distance moved by an object along a

particular direction. Speed is distance travelled per unit time. Velocity is rate of change of displacement. Acceleration is rate of change of velocity. Scalar quantity is one which has magnitude but no direction. Vector is a quantity which has direction as well as magnitude. Note: If an object is moving at constant speed, the resultant force is zero.

Force is push or pull that change the state of motion of an object.

Note

 If a car is driving around a circle at a constant speed, its  is not constant. The Car is accelerating. (Because Velocity has magnitude and direction. When the car is turning around the circle, its direction changes constantly)

Newtons laws of motion

Newton’s First Law: A body continues in its state of rest or uniform motion in a straight line unless a resultant external force acts on it. Newton’s Second Law: The rate of change of momentum of a body is proportional to the resultant force acting on it and occurs in the direction of the force. Newton’s Third Law: Every action there is an equal and opposite reaction. Momentum is the product of the mass of an object and its velocity. Principle of moments: The sum of clockwise moments about a point is equal to the sum of anti‐clockwise moments about the same point.

Moment of a force 

Moment of a force about a point is the turning effect it causes on the body about the pivot.

Moment = Force x Perpendicular distance from pivot.

Center of Gravity/Mass: The point which the weight of the object appears to act.

Hooke’s Law

The force needed to cause an extension in a spring is directly proportional to its extension. Upthrust is the upward force acting on an object that is partially or fully immersed in a fluid. Density is mass per unit volume. Kinetic energy is the ability to do work due to the object’s speed. Gravitational Potential energy is the ability to do work due to the object’s height. Inertia is an object’s resistance to a change in velocity. (Heavier objects have greater inertia) Work Done is the product of a force and the displacement in the direction of the force. Energy is the ability of work done. Power is rate of work done or rate of energy transfer. Pressure is force per unit area.