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03:23Types of Radioactivity
The most common types of radioactivity are α decay, β decay, γ decay, neutron emission, and electron capture.
Alpha (α) decay is the emission of an α particle from the nucleus. For example, polonium-210 undergoes α decay:
Alpha (α) decay is the emission of an α particle from the nucleus. For example, polonium-210 undergoes α decay:
02:50Nuclear Fission
Many heavier elements with smaller binding energies per nucleon can decompose into more stable elements that have intermediate mass numbers and larger binding energies per nucleon—that is, mass numbers and binding energies per nucleon that are closer to the “peak” of the binding energy graph near 56. Sometimes neutrons are also produced. This decomposition of a large nucleus into smaller pieces is called fission. The breaking is rather random with the formation of a large number of different...
01:07Free-falling Bodies: Introduction
All objects, neglecting air resistance, fall with the same acceleration towards the Earth's center due to the force exerted by the Earth's gravity. This experimentally determined fact is unexpected because we are so accustomed to the effects of air resistance and friction that we expect light objects to fall slower than heavier ones. People believed that a heavier object had a greater acceleration when falling until Galileo Galilei (1564–1642) proved otherwise. We now know this is not the case.
01:05Free-falling Bodies: Example
An object falling without any air resistance under the influence of gravitational force is said to be in free-fall. For free-falling bodies, the acceleration due to gravity is constant, irrespective of their mass. Free-fall is experienced not only by objects falling downward, but also by all objects whose motion is influenced by gravitational force alone. The dynamics of free-fall motion can be calculated using kinematic equations of motion, since free-fall acceleration is constant.
The...
The...
01:20Projectile Motion
An object thrown in the air follows a parabolic path under the influence of Earth's gravitational force. The motion of such an object is called projectile motion, and the object itself a projectile. The parabolic path followed by the projectile is called the trajectory. Some common examples of projectile motion are the launching of fireworks, a golf ball in the air, meteors entering the Earth's atmosphere, and the firing of bullets.
When an object falls under gravity and has no horizontal...
When an object falls under gravity and has no horizontal...
01:19Types of Collisions - II
When two or more objects collide with each other, they can stick together to form one single composite object (after collision). The total mass of the object after the collision is the sum of the masses of the original objects, and it moves with a velocity dictated by the conservation of momentum. Although the system's total momentum remains constant, the kinetic energy decreases, and thus such a collision is an inelastic collision. Most of the collisions between objects in daily life are...