A runner stood at the 100-meter mark on a track. When the timer started, the runner sprinted north to the 200-meter mark. It too
1 answer:
Answer:
4m/sec north
Explanation:
Given the runner sprinted from 100m mark to 200m mark, which means the displacement of the runner is 200-100=100m.
Now given the time taken to travel this 100 distance is 25 seconds
We know that Average velocity =
Average velocity = = 4 m/sec.
We can observe from the above formulae that the direction of the average velocity is in the direction of the displacement which is given north.
Therefore the Average velocity of the runner is 4m/sec north
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Answer:
37.5 mL of a 4.0 M Mg(OH)₂ are needed to make 750 mL of 0.2 M Mg(OH)₂
Explanation:
Dilution is the reduction in concentration of a chemical in a solution. Dilution consists of lowering the amount of solute per unit volume of solution.
In other words, dilution is the procedure followed to prepare a less concentrated solution from a more concentrated one, and consists of adding solvent to an existing solution. The quantity or mass of the solute is not changed but only that of the solvent.
In dilutions the expression is used:
Ci*Vi = Cf*Vf
where:
- Ci: initial concentration
- Vi: initial volume
- Cf: final concentration
- Vf: final volume
In this case:
- Ci: 4 M
- Vi: ?
- Cf: 0.2 M
- Vf: 750 mL
Replacing:
4 M* Vi= 0.2 M* 750 mL
Solving:
Vi= 37.5 mL
<u><em>37.5 mL of a 4.0 M Mg(OH)₂ are needed to make 750 mL of 0.2 M Mg(OH)₂</em></u>