Physics Spl

When all the forces act on a single object, a free body diagram (FBD) graphically represents these forces. It helps in analyzing the net effect of the forces by isolating the object from its environment. An arrow pointing in the direction of a force represents a force and its magnitude is also labeled. FBDs allow systematic application of Newton's laws and hence are crucial in solving mechanics problems. For example on an inclined plane, in a block, the FBD helps identify normal, gravitational, and frictional forces acting on the block.

Inertia is the body's inherent property to resist any change in its state of rest or motion. Newton's First Law of Motion says that unless an external force is applied to an object, it will not change its state (rest or motion). Hence, the first law of Newton defines inertia. It also says that if the mass of an object is more then the inertia will also be more. For example, a loaded truck is harder to push than an empty one due to the fact that a loaded truck has more inertia.

When two waves of the same amplitude, frequency and speed travel in opposite directions and collide with each other, then a standing wave is formed. It is usually seen in the bounded medium, like a string fixed at both ends. It is different from the travelling waves and does not appear to move along the medium. At fixed locations, it forms specific points called nodes (with zero displacement) and antinodes (with maximum displacement). It is an important concept in understanding musical instruments, resonance and wave behaviour in closed and open pipes. The standing waves help in visualizing how energy can be stored in waveforms.

Mechanical waves are of two types - transverse waves and longitudinal waves. It requires a medium to travel. The medium particles vibrate perpendicular to the direction of wave propagation in the case of transverse waves.  However, the particles oscillate parallel to the wave direction in the longitudinal waves as seen in sound waves. The sound waves propagate by exerting forces by the neighbouring particles. While the wave particles stay close to the original position, the energy is passed on through the interactions among the adjacent particles.

A disturbance that travels through the space or medium transferring energy without the net movement of particles is called a wave. Rather than moving along with the wave, the particles of the medium only oscillate about their mean position in a wave motion. The wave is fundamentally different as compared to the particle motion where the particles travel from one place to another. In a sound wave, the air molecules do not travel to the sound, they vibrate back and forth. The concept of wave motion is one of the most important concepts in knowing how energy is transmitted in various forms including light, sound and water waves.