Physics Principles: Laws of Motion, Buoyancy, Elasticity, and Thermodynamics - Prof. A. Bu | Study notes Physics

-1st law: NO NET FORCE acts on an object; it will keep doing what its doing-maintain zero velocity or

maintain a constant speed in a straight line. No change in VELOCITY- no ACCELERATION.

-2nd law: IF A NET FORCE does act on an object; the object will ACCELERATE, and the acceleration will be

in direct proportion to the net force (bigger force-bigger acceleration). The acceleration will be in

inverse proportion to the object’s mass (bigger mass-smaller acceleration). The acceleration will be in

the same DIRECTION as the NET force. Fnet=(m)(a)

-3rd law: FORCES ALWAYS OCCUR IN PAIRS. If a force acts on an object, there will always be a second

force that acts on a DIFFERENT object. This second force will be the SAME MAGNITUDE as the force on

the first object, but will be in the OPPOSITE direction.

The weight is always the same. Weight is ALWAYS equal to the buoyant force. W down. N up. B up. Ups

EQUAL downs. Drag acts opposite to motion.

-A: Sunken object: W, N, B. At rest and remaining at rest. EF=0, a=0. Weight of the fluid displaced is less

than the weight of the object. Volume of the fluid displaced equals the volume of the object.

-B: Neutrally buoyant object: W, B: cancel each other out. Weight of the fluid displaced equals the

weight of the object. Volume of the fluid displaced equals the volume of the object.

-C: Floating object: W, B: if something is floating there is no normal force. Weight of the fluid displaced

equals the weight of object. Volume of the fluid displaced (is half) is less than the volume of the object.

-Mechanical equilibrium: EF=0, a=0. Some of the forces are equal to zero. Forces are equal and opposite.

-Archimedes’ Principle: B= weight of the fluid displaced.

-The “density” rule: If one increases the other decreases. Less dense float, denser sinks.

-van Der Waals forces: the mechanism that provides adhesion of the many ridges in the feet of a gecko.

-All materials are elastic ON AN ATIOMIC LEVEL. On a larger scale, “inelastic” materials can have their

atoms pushed past each other permanently. (Being pushed passed) Atomic bonds give rise to the

NORMAL FORCE from solids.

-Gas molecules also behave like “masses on springs”- an oxygen molecule is two oxygen atoms bonded

together. However, EMPTY SPACE in between gas molecules gives rise to their COMPRESSIBILITY. This

gives rise to the fact that the atmosphere is denser at the bottom than the top. Spread out.

-Solids and liquids are said to be “practically incompressible”. This means their density is CONSTANT.

This is important when dealing with liquid density. The same at the top and bottom. Atoms in solids and

liquids are “very” close together.

-“Elastic” materials (gives rise to the normal force, spring. KE is conserved) deform when a force is

applied AMD return to their original shape when the force is removed. “Inelastic” materials (clay, putty)

such as dough will not return to their original shape when the force is removed. If the elastic limit of a

material is reached, the material will no longer return to its original shape. (Loses to thermal energy,

sticks to a wall.)

-Elasticity leads to compressibility, which leads to pushing the molecules closer together, which

decreases the space.

-Hooke’s Law: applies only to some elastic materials, more all. Rubber bands are an exception. Can be

used to determine the amount of stretch of many elastic materials, given the amount of MASS or

WEIGHT that is hung on a material (such as a spring). The amount of stretch is always compared to the

length of the material without any force applied. Only as long as the force does not stretch or compress

the material to its elastic limit.

-Liquid pressure and solid pressure both represent a force per unit area.

-Atmospheric pressure= weight of the atmosphere above us divided by surface area.

-Bernoulli’s Principle: As the speed of a fluid increases, its internal pressure decreases.

Partial preview of the text

Download Physics Principles: Laws of Motion, Buoyancy, Elasticity, and Thermodynamics - Prof. A. Bu and more Study notes Physics in PDF only on Docsity!

-1st^ law: NO NET FORCE acts on an object; it will keep doing what its doing-maintain zero velocity or maintain a constant speed in a straight line. No change in VELOCITY- no ACCELERATION. -2nd^ law: IF A NET FORCE does act on an object; the object will ACCELERATE, and the acceleration will be in direct proportion to the net force (bigger force-bigger acceleration). The acceleration will be in inverse proportion to the object’s mass (bigger mass-smaller acceleration). The acceleration will be in the same DIRECTION as the NET force. Fnet=(m)(a) -3rd^ law: FORCES ALWAYS OCCUR IN PAIRS. If a force acts on an object, there will always be a second force that acts on a DIFFERENT object. This second force will be the SAME MAGNITUDE as the force on the first object, but will be in the OPPOSITE direction. The weight is always the same. Weight is ALWAYS equal to the buoyant force. W down. N up. B up. Ups EQUAL downs. Drag acts opposite to motion. -A: Sunken object: W, N, B. At rest and remaining at rest. EF=0, a=0. Weight of the fluid displaced is less than the weight of the object. Volume of the fluid displaced equals the volume of the object. -B: Neutrally buoyant object: W, B: cancel each other out. Weight of the fluid displaced equals the weight of the object. Volume of the fluid displaced equals the volume of the object. -C: Floating object: W, B: if something is floating there is no normal force. Weight of the fluid displaced equals the weight of object. Volume of the fluid displaced (is half) is less than the volume of the object. -Mechanical equilibrium: EF=0, a=0. Some of the forces are equal to zero. Forces are equal and opposite. -Archimedes’ Principle: B= weight of the fluid displaced. -The “density” rule: If one increases the other decreases. Less dense float, denser sinks. -van Der Waals forces: the mechanism that provides adhesion of the many ridges in the feet of a gecko. -All materials are elastic ON AN ATIOMIC LEVEL. On a larger scale, “inelastic” materials can have their atoms pushed past each other permanently. (Being pushed passed) Atomic bonds give rise to the NORMAL FORCE from solids. -Gas molecules also behave like “masses on springs”- an oxygen molecule is two oxygen atoms bonded together. However, EMPTY SPACE in between gas molecules gives rise to their COMPRESSIBILITY. This gives rise to the fact that the atmosphere is denser at the bottom than the top. Spread out. -Solids and liquids are said to be “practically incompressible”. This means their density is CONSTANT. This is important when dealing with liquid density. The same at the top and bottom. Atoms in solids and liquids are “very” close together. -“Elastic” materials (gives rise to the normal force, spring. KE is conserved) deform when a force is applied AMD return to their original shape when the force is removed. “Inelastic” materials (clay, putty) such as dough will not return to their original shape when the force is removed. If the elastic limit of a material is reached, the material will no longer return to its original shape. (Loses to thermal energy, sticks to a wall.) -Elasticity leads to compressibility, which leads to pushing the molecules closer together, which decreases the space. -Hooke’s Law: applies only to some elastic materials, more all. Rubber bands are an exception. Can be used to determine the amount of stretch of many elastic materials, given the amount of MASS or WEIGHT that is hung on a material (such as a spring). The amount of stretch is always compared to the length of the material without any force applied. Only as long as the force does not stretch or compress the material to its elastic limit. -Liquid pressure and solid pressure both represent a force per unit area. -Atmospheric pressure= weight of the atmosphere above us divided by surface area. -Bernoulli’s Principle: As the speed of a fluid increases, its internal pressure decreases.

-LoCoE: energy cannot be created nor destroyed. It may be transformed from one form to another, but the total amount of energy never changes. Applies to a closed system, no energy going in or out. -LoCoM: only applies to a closed system, no outside or external forces. Is a vector. -Work: product of the force on an object and the distance through which the object is moved; measured in Joules. -Energy- That which can change the conditions of matter. The ability to do work. -Work-energy theorem- Work done on an object is equal to the KE gained by the object. -Impulse- Product of force and the time interval during which the force acts; the change in momentum. -Momentum- Inertia in motion. The product of the mass and the velocity of an object. Has magnitude and direction and therefore is a vector quantity. -Friction is the resistance to motion or a tendency toward motion that may occur when two solids are in contact. Laws of thermodynamics: First law is the restatement of the LoCoE, when thermal energy is included. When heat flows to or from a system, the system gains or loses an amount of energy equal to the amount of heat transferred. (Heat added= increase in thermal energy+ external work). Second Law: Heat of itself never flows from a cold object to a hot object. -Latent heat is a form of potential energy on a particle scale. -The period of a wave does not depend on the mass of the pendulum or the size of the arc through which it swings. (The mass doesn’t matter). LENGTH and GRAVITY affect the period. When you double the period it makes the length 4 times as long. -Frequency is HOW MANY oscillations that occur in 1 second and the period is HOW LONG it takes to complete one oscillation. -Standing waves exhibit nodes and antinodes, has stationary crest/trough or compression/rarefaction.

Physics Principles: Laws of Motion, Buoyancy, Elasticity, and Thermodynamics - Prof. A. Bu, Study notes of Physics

Related documents

Partial preview of the text

Download Physics Principles: Laws of Motion, Buoyancy, Elasticity, and Thermodynamics - Prof. A. Bu and more Study notes Physics in PDF only on Docsity!