PHYSICS DEFINITIONS:
CHAPTER 1: FORCE
1. Moment of force: product of the magnitude of the force and the
perpendicular distance of the line of action of the force from the axis of
rotation.
2. Couple: The two equal opposite and parallel forces not acting along the
same line, form a couple.
3. State of Equilibrium: When a number of forces acting on a body produce
no change in its state of rest or of linear or rotational motion, the body is
said to be in equilibrium.
4. Static equilibrium: When a body remains at a state of rest under the
influence of several forces, the body is said to be at static equilibrium.
5. Dynamic equilibrium: When a body remains at a state of motion under
the influence of several forces, the body is said to be at dynamic
equilibrium. Note: anti-clockwise
moments. Is taken positively.
6. Principle of moments: In equilibrium, While clockwise moments is
taken negatively
Sum of clockwise moments = Sum of anti-clockwise moments.
7. Centre of Gravity: Centre of Gravity of a body is the point about which
the algebraic sum of moments of all weights of particles is zero . The
entire weight of the body can be considered the act at this point,
howsoever the body is placed.
, 8. Uniform circular motion: When a particle moves with constant speed in
a circular path then the body is said to be uniform circular motion.
9. Centripetal force : The force acting on a body in a circular path, in a
direction towards the centre of the circular path.
10.Centrifugal force: A force assumed (by an observer moving with the
body) to be acting on the body in a direction away from the centre of
the circular path.
CHAPTER 2: WORK POWER ENERGY
1. Work : work is said to be done only when the force applied on a body
makes the body move.(THERE IS DISPLACEMENT OF THE BODY )
OR
1. WORK: The amount of work done by a force is equal to the product of force
and displacement of the point of application of the force in the direction of
the force.
2. joule: 1 J of work is said to be done when a force of 1 N displaces the body
by 1 m in its own direction .
3. erg: 1 erg of work is said the be done when a force of 1 dyne displaces the
body by 1 cm in its own direction.
4. Power: The rate of doing work is called power.
5. watt: If one J of work is done in one second then the power spent is said to
be 1 watt.
6. Energy: The capacity to do work is called energy
, 7. Potential energy: The energy possessed by a body at rest due to its position
or size and shape.
8. Gravitational potential energy: The potential energy possessed by a body
due force of attraction of the Earth on it, is called gravitational potential
energy.
9. Elastic potential energy: The potential energy possessed by a body in the
deformed state due to change in its size and shape is called elastic
potential energy.
10. Kinetic energy: the energy possessed by a body due to its state of motion.
11. Momentum: Momentum is a property of a moving body that is equal to the
product of its mass and velocity.
12. Work-energy theorem: The increase in Kinetic energy of a moving body is
equal to the work done by a force acting in the direction of the moving
body.
13. Translational kinetic energy: the kinetic energy of a body due to its motion
in a straight line.
14. Rotational kinetic energy: kinetic energy of a body due to its rotational
motion.
15. Vibrational kinetic energy: kinetic energy of a body due to its vibrational
motion.
16. Mechanical energy: the energy possessed by a body due to its state of rest
or motion is called mechanical energy. it is the sum of potential and kinetic
energy.
17. Dissipation of energy: While transformation of energy from one form to
another desired form, the entire energy does not change into the desired
CHAPTER 1: FORCE
1. Moment of force: product of the magnitude of the force and the
perpendicular distance of the line of action of the force from the axis of
rotation.
2. Couple: The two equal opposite and parallel forces not acting along the
same line, form a couple.
3. State of Equilibrium: When a number of forces acting on a body produce
no change in its state of rest or of linear or rotational motion, the body is
said to be in equilibrium.
4. Static equilibrium: When a body remains at a state of rest under the
influence of several forces, the body is said to be at static equilibrium.
5. Dynamic equilibrium: When a body remains at a state of motion under
the influence of several forces, the body is said to be at dynamic
equilibrium. Note: anti-clockwise
moments. Is taken positively.
6. Principle of moments: In equilibrium, While clockwise moments is
taken negatively
Sum of clockwise moments = Sum of anti-clockwise moments.
7. Centre of Gravity: Centre of Gravity of a body is the point about which
the algebraic sum of moments of all weights of particles is zero . The
entire weight of the body can be considered the act at this point,
howsoever the body is placed.
, 8. Uniform circular motion: When a particle moves with constant speed in
a circular path then the body is said to be uniform circular motion.
9. Centripetal force : The force acting on a body in a circular path, in a
direction towards the centre of the circular path.
10.Centrifugal force: A force assumed (by an observer moving with the
body) to be acting on the body in a direction away from the centre of
the circular path.
CHAPTER 2: WORK POWER ENERGY
1. Work : work is said to be done only when the force applied on a body
makes the body move.(THERE IS DISPLACEMENT OF THE BODY )
OR
1. WORK: The amount of work done by a force is equal to the product of force
and displacement of the point of application of the force in the direction of
the force.
2. joule: 1 J of work is said to be done when a force of 1 N displaces the body
by 1 m in its own direction .
3. erg: 1 erg of work is said the be done when a force of 1 dyne displaces the
body by 1 cm in its own direction.
4. Power: The rate of doing work is called power.
5. watt: If one J of work is done in one second then the power spent is said to
be 1 watt.
6. Energy: The capacity to do work is called energy
, 7. Potential energy: The energy possessed by a body at rest due to its position
or size and shape.
8. Gravitational potential energy: The potential energy possessed by a body
due force of attraction of the Earth on it, is called gravitational potential
energy.
9. Elastic potential energy: The potential energy possessed by a body in the
deformed state due to change in its size and shape is called elastic
potential energy.
10. Kinetic energy: the energy possessed by a body due to its state of motion.
11. Momentum: Momentum is a property of a moving body that is equal to the
product of its mass and velocity.
12. Work-energy theorem: The increase in Kinetic energy of a moving body is
equal to the work done by a force acting in the direction of the moving
body.
13. Translational kinetic energy: the kinetic energy of a body due to its motion
in a straight line.
14. Rotational kinetic energy: kinetic energy of a body due to its rotational
motion.
15. Vibrational kinetic energy: kinetic energy of a body due to its vibrational
motion.
16. Mechanical energy: the energy possessed by a body due to its state of rest
or motion is called mechanical energy. it is the sum of potential and kinetic
energy.
17. Dissipation of energy: While transformation of energy from one form to
another desired form, the entire energy does not change into the desired
