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Rainbow [258]
3 years ago
6

3. Reducing friction in a machine

Physics
1 answer:
Zarrin [17]3 years ago
4 0

Answer:

C

B

C

Explanation:

To increase the efficiency of a machine, it is advisable that one reduces friction within the machine parts as much as possible through common procedures such as greasing and oiling. This is helps to reduce the amount of energy lost due to friction hence contributing to output which finally is useful in calculating efficiency of a machine.

Efficiency can't be 100% since it is found by dividing work output verses input but the output is usually slightly less than the input energy due to energy losses within a machine. The losses that occur are mainly attributed to frictional losses.

Here efdiciency and work output are given but input is missing. Converting efficiency into decimal we have 0.75 and since efficiency=output/input then the input will be given by output/efficiency and by substitution 240/0.75=320 J

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By starting with a falsifiable hypothesis and proceeding to gather data and ensure replicability, a scientist can contribute to
maksim [4K]

Answer:

theory

Explanation:

<em>A scientist can contribute to the formation of a theory in a particular subject by conducting research along the line of that subject.</em>

Conducting research requires the formation of a hypothesis and testing the hypothesis by conducting a relevant experiment during which data are gathered, analyzed, and interpreted in order to falsify or accept the hypothesis.

A good experiment must be replicate-able. When the same experiment is repeated by different independent researchers and the same conclusion is arrived at, this could potentially lead to the formation of a theory.

<u>Hence, a scientist can contribute to the formation of a theory by conducting an experiment with replicability in order to test a hypothesis.</u>

8 0
3 years ago
How long does it take a person at rest to breathe one mole of air if the person breathes 77.0 ml/s of air that is measured at 25
Natali5045456 [20]
<span>320. seconds The ideal gas law is PV = nRT where P = pressure of the gas V = volume of the gas n = number of moles of the gas R = the ideal gas constant T = absolute temperature of the gas. Since we're going to want the volume, solve for V PV = nRT V = nRT/P 755 mmHg converts to 100658.11 Pascals 25 C = 298.15 K Let's calculate nT/P, then we'll multiply by R 1 mol * 298.15 K / 100658.11 Pa = 0.002962007 K mol/Pa The value for R in the most convenient units is 8.3144598 m^3 Pa/(K mol), so 0.002962007 K mol/Pa * 8.3144598 m^3 Pa/(K mol) = 0.024627486 m^3 So 1 mole of air at the specified temperature and pressure has a volume of 24.627 liters. The rest of the problem is now trivial. Just divide by the rate of consumption, so 24.627 l / 0.0770 l/s = 319.8374798 s Rounding the result to 3 significant figures gives 320. seconds.</span>
4 0
3 years ago
Which of the following can influence one’s ability to detect stimuli and increase one’s responsiveness to stimuli in dangerous s
Keith_Richards [23]
The correct answer is Response Criteria.
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4 years ago
Read 2 more answers
Water has a mass per mole of 18.0 g/mol, and each water mo- lecule (H2O) has 10 electrons. (a) How many electrons are there in o
Dovator [93]

Answer:

a) There are 3,35*10^{26} electrons in a liter of water.

b) The net charge is -53601707,1 C

Explanation:

a) To find out how many electrons are in a liter of water (equivalent to 1000 grams of water), we have to find out how many molecules of water there are and then multiply it by 10 (e- per molecule).

We can find out how many molecules are by finding the number of moles and then multiplying it by Avogadro's number (number of elements per mol):

e^{-}= \frac{m_{water} }{M_{water} } * Avogadro* \frac{e^{-} }{molecule}=  \frac{1000g }{18g/mol} * 6,022*10^{23} * \frac{10e^{-} }{molecule}=3,35*10^{26} e^{-}

b) As all electrons have the same charge, in order to find the net charge of those electrons we have to multiply the charge of a single electron by the number of electrons:

Net charge= -1,602*10^{-19}  \frac{C}{e^{-} }  *3,35*10^{26} e^{-}=-53601707,1 C

An important clarification is that while the net charge may seem huge, water as a whole is a neutral medium, because there are as many protons as there are electrons, and as they have the same charge, the net charge of water is 0.

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4 years ago
When large amplitude sound vibrates the ear significantly, a _______ results.
sladkih [1.3K]

The answer is B. High Pitch Sound

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