B. Sand.
Sand would definitely increase friction because of the roughness of it surface. When its surface comes with another rough surface it would tend to increase friction. All other options given tend to reduce friction one way or the other.
Explanation:
Given that:
Distance traveled = 3150m
Average speed = 350m/min
Suggested speed = 375m/min
Unknown:
Time = ?
Solution:
Speed is the rate of change of distance with time.
it is mathematically expressed as;
speed =
Initial time using speed 350m/min can be calculated by making time the subject of the formula;
time taken =
time taken at speed of speed of 350m/min = = 9min
to seconds = 9 x 60 = 540 seconds
time taken at speed of 375m/min = = 8.4min
to seconds = 8.4 x 60 = 504 seconds.
It could have taken 504 seconds sooner saving 36 seconds.
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Species that have a lone pair of electrons often donate electrons by resonance while substituents that are electron deficient take away electrons by resonance.
<h3>What is resonance?</h3>
The term resonace has to do with the movement of electron pairs in a molecule. Inductive effects has to do with the drawing of electron density towards an atom or bond.
The two effects depends on the nature of a substituent. For instance, species that have a lone pair of electrons often donate electrons by resonance while substituents that are electron deficient take away electrons by resonance.
The question is incomplete hence the exact nature of the substituents can not be determined.
Learn more about resonance: brainly.com/question/23287285?