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The actual mechanical advantage of a pulley is 2. The pulley has 3 supporting strings. What is the efficiency of the pulley?
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KGUS eNotes educator | CERTIFIED EDUCATOR
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The efficiency of a simple machine can be expressed as the ratio of the actual mechanical advantage divided by the theoretical mechanical advantage. You were given the actual mechanical advantage as 2, so you only need to determine the theoretical mechanical advantage. With a pulley system, this becomes a simple matter of determining how many strings support the pulley, which was nicely given as three. Therefore, the efficiency in this case is 2/3, or about 67%.
The concepts used to solve this exercise are given through the calculation of distances (from the Moon to the earth and vice versa) as well as the gravitational potential energy.
By definition the gravitational potential energy is given by,
Where,
m = Mass of Moon
G = Gravitational Universal Constant
M = Mass of Ocean
r = Radius
First we calculate the mass through the ratio given by density.
PART A) Gravitational potential energy of the Moon–Pacific Ocean system when the Pacific is facing away from the Moon
Now we define the radius at the most distant point
Then the potential energy at this point would be,
PART B) when Earth has rotated so that the Pacific Ocean faces toward the Moon.
At the nearest point we perform the same as the previous process, we calculate the radius
The we calculate the Potential gravitational energy,
Digestive system: consists of the gastrointestinal tract plus the accessory organs of digestion. Digestion involves the breakdown of food into smaller and smaller components, until they can be absorbed and assimilated into the body.
Endocrine system: a chemical messenger system comprising feedback loops of the hormones released by internal glands of an organism directly into the circulatory system, regulating distant target organs.
Eukaryotes: organisms whose cells have a nucleus enclosed within a nuclear envelope.
Excretory system: an organism's body that performs the function of excretion, the bodily process of discharging wastes.
Golgi Apparatus/complex: an organelle found in most eukaryotic cells. Part of the endomembrane system in the cytoplasm, it packages proteins into membrane-bound vesicles inside the cell before the vesicles are sent to their destination.
Lysosome: a membrane-bound cell organelle that contains digestive enzymes. They break down excess or worn-out cell parts. They may be used to destroy invading viruses and bacteria.
Mitochondria: a membrane-bound cell organelles that generate most of the chemical energy needed to power the cell's biochemical reactions.
Muscular system: an organ system consisting of skeletal, smooth and cardiac muscles. It permits movement of the body, maintains posture and circulates blood throughout the body
Nervous system: the network of nerve cells and fibers which transmits nerve impulses between parts of the body.
Nucleus: a membrane-bound organelle that contains DNA of eukaryotic organisms. As such, it serves to maintain the integrity of the cell by facilitating transcription and replication processes.
Organ: a group of tissues in a living organism that have been adapted to perform a specific function.
Organism: an individual animal, plant, or single-celled life form.
Organ system: a group of organs that work together as a biological system to perform one or more functions
Prokaryotes: a microscopic single-celled organism that has neither a distinct nucleus with a membrane nor other specialized organelles.
Ribosome: a minute particle consisting of RNA and associated proteins found in large numbers in the cytoplasm of living cells. They bind messenger RNA and transfer RNA to synthesize polypeptides and proteins.
Respiratory system: a biological system consisting of specific organs and structures used for gas exchange in animals and plants.
Rough endoplasmic reticulum: an organelle found in eukaryotic cells. Its main function is to produce proteins. It is made up of cisternae, tubules and vesicles.
Skeletal system: The human skeleton is the internal framework of the human body.
Smooth ER: is a membranous organelle found in most eukaryotic cells
Tissue: a group of cells, in close proximity, organized to perform one or more specific functions.
Vacuole: a membrane-bound organelle.
<span>c. both protons and electrons</span>
Answer:
The Density of the block is 4.667g/mL
Explanation:
Given the following data;
Mass of block = 700g
Volume of block = 150cm³
Density = ?
Density can be defined as mass all over the volume of an object.
Simply stated, density is mass per unit volume of an object.
Mathematically, density is given by the equation;
Substituting into the equation, we have;
<em>Density = 4.667g/mL</em>