The efficiency of the steam engine is 78.9% because the rest of the work input is used to overcome friction.
<h3>What is efficiency of machines?</h3>
Efficiency of a machine expresses the useful work done by a a machine as a percentage.
- Efficiency of a machine = work output/work input × 100 %%
The efficiency of machines are always less than 100% percent due to energy losses due to friction and heat.
For the steam engine:
Work output = 225 J
Work input = 285 J
Efficiency = 225/285 × 100% = 78.9 %
Therefore, the efficiency of the steam engine is 78.9% because the rest of the work input is used to overcome friction.
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40 km/h because the average of 50 and 30 is 40
Answer:
Chloromethane experiences dipole-dipole interactions.
Chloromethane has a higher molar mass than hydrogen.
Explanation:
The molar mass is directly proportional to the heat of fusion, since the heavier the molecules the more energy they need to separate. Intermolecular forces are also directly proportional to the heat of fusion, because the greater the interaction they experience, the more energy they require to separate. The dipole-dipole interactions experienced by chloromethane are stronger than the interactions that take place in hydrogen.
Answer:
C) steel turning to rust in salt air
Explanation:
The missing options are:
A) ice melting to form liquid water
B) water boiling to form steam
C) steel turning to rust in salt air
D) sugar dissolving into hot coffee
In a chemical change the atoms of the reacting compounds are reordered forming new compounds. In a chemical change, new compounds appear, but in a physical change not.
Then, change of states like ice melting and water boiling are not chemical changes.
During steel rust, components of steel, like iron, are oxidized, that is, reacts with oxygen forming oxides.
The dissolution of sugar into hot coffee is a physical change in which sugar molecules get further apart in the coffee, but they don't change.