Physics book report
Name of the book: Physics for the utterly confused
The things I learnt from the book are as follows:
1. 1. An object weighs less on the moon, but it has the same mass
2. 2. For objects close to the surface of the earth, the acceleration of gravity is equal to “little g” or 9.8ms-2. For objects farther from the surface of the earth(10km and above, roughly) use the universal gravitational constant, big G, to find the force of gravity.
1. 1. impulse = average force × △t, where △t is the amount of time over which the force acts. In most problems we assume that a constant force acts for a certain amount of time. The SI units are Ns.
2. 2. p = mv is the definition of momentum. Remember that momentum, as velocity, is a vector. The SI units of momentum are kg m/s
3. 3. Momentum is always conserved in a collision and kinetic energy is sometimes conserved. An elastic collision (billiard balls) is one where kinetic energy is conserved. An inelastic collision (lumps of clay) is one in which kinetic energy is not conserved. The objects stick together in an inelastic collision.
Sign conventions for mirrors:
(i) The distance is the distance of the object from the surface of the mirror:
“o” is positive if the object is in front of the mirror
“o” is negative if the object is in back of the mirror
(ii) The image distance is the distance f the image from the surface of the mirror:
“i” is positive if the image is in front of the mirror
“i” is negative if the image is in back of the mirror
(iii) The focal point is the point where light rays converge from a mirror:
“f” is positive if the center of curvature is in front of the mirror
“f” is negative if the center of curvature is in back of the mirror
The sign conventions for “f” are the same for “R”, the radius of curvature.
Sign conventions for lenses:
“o” is positive if the object is in front of the lens
“o” is negative if the object is in back of the lens
“i” is positive if the image is in back of the lens
”i” is negative if the image is in front of the lens
“f” is positive for converging lens
“f” is negative for a diverging lens
After reading this book, I know more about physics. All the things are very clear and I can understand it very well. The topics in this book are affluent, electricity, wave, sound, forces and so on. I would read this book before having physics lesson. If I do not pay attention during the lesson, this book can show me some physics concept and help me learn more clearly.
I will recommend this book to my classmates because it really can help us a lot. Physics is a very difficult subject, we cannot learn without tutorial books. Whoever reads this book, his physics will be very good.