10th Class Physics Chapter 1 Notes Urdu Medium

Important 10th Class Physics Chapter 1 Notes Urdu Medium in 10th Class Physics Urdu Medium written by Professor Sir Fahad Abbas Suib. These computerized notes are very helpful in the preparation of 10th Class Physics Chapter 1 Notes Urdu Medium for students of the 10th class Physics and these are according to the paper patterns of all Punjab boards.

• Such type of motion in which an object performs periodic motion under the influence of restoring force is called Simple Harmonic Motion (SHM).  OR   A special oscillatory motion in which restoring force is directly proportional to the displacement and displacement is directed towards the mean position is called Simple Harmonic Motion and the object is called Simple Harmonic Oscillation.
• Conditions for Simple Harmonic Motion: The motion should be periodic. The motion should be under the influence of restoring force. Acceleration should be directly proportional to the displacement and directly towards the main position
• Example of simple harmonic motion: Motion of mass-spring system, the motion of the simple pendulum, motion of the physical pendulum, motion of the torsional pendulum, motion of projection of particle moving in a vertical circle
• "A body is said to be vibrating if it moves back and forth or to and fro about a point". Another term for vibration is oscillation. A special kind of vibratory or oscillatory motion is called the simple harmonic motion (SHM), which is the main focus of this chapter. We will discuss important characteristics of SHM and systems executing SHM. We will also introduce different types of waves and will demonstrate their properties with the help of ripple tank.
• SIMPLE HARMONIC MOTION (SHM): In the following sections we will discuss simple harmonic motion of different systems. The motion of mass attached to a spring on a horizontal frictionless surface, the motion of a ball placed in a bowl and the motion of a bob attached to a string are examples of SHM.
• MOTION OF MASS ATTACHED TO A SPRING: One of the simplest types of oscillatory motion is that of horizontal mass-spring system. If the spring is stretched or compressed through a small displacement x from its mean position, it exerts a force F on the mass. According to Hooke’s law this force is directly proportional to the change in length x of the spring i.e.,
• F = - k x, where x is the displacement of the mass from its mean position O, and k is a constant called the spring constant defined as k = - F / x
• The value of k is a measure of the stiffness of the spring. Stiff springs have large value of k and soft springs have small value of k. As or F = ma Therefore, k = - ma / x, a = - k x /m
• It means that the acceleration of a mass attached to a spring is directly proportional to its displacement from the mean position. Hence, the horizontal motion of a mass-spring system is an example of simple harmonic motion.
• State the conditions necessary for an object to oscillate with SHM.
• Explain SHM with simple pendulum, ball and bowl examples.
• Draw forces acting on a displaced pendulum.
• solve problems by using the formula T = 2π l /g for simple pendulum. 
• Understand that damping progressively reduces the amplitude of oscillation.
• Describe wave motion as illustrated by vibrations in rope, slinky spring and by experiments with water waves.
• Describe that waves are means of energy transfer without transfer of matter.
• Distinguish between mechanical and electromagnetic waves.
• Identify transverse and longitudinal waves in mechanical media, slinky and springs.
• Define the terms speed (v), frequency (f), wavelength (λ), time period (T), amplitude, crest, trough, cycle, wavefront, compression and rarefaction.
• Derive equation v = f λ.
• Solve problems by applying the relation f = 1/T and v = f λ.
• Describe properties of waves such as reflection, refraction and diffraction with the help of ripple tank.
• Explain the diffraction of radiowaves but not of T.V waves (transmission can be heard in such areas where the waves cannot reach directly).