You spot a friend walking on a moving walkway in an airport. You are not on the walkway and you want to keep up with her.At what speed do you need to walk?

A. the speed of the walkway multiplied by the speed at which she is walking

B. the speed of the walkway minus the speed at which she is walking

C. the speed of the walkway plus the speed at which she is walking

Answer:

The time saved on a ten mile trip by traveling at 60 mph instead of 55 mph is 54 seconds

Explanation:

Velocity ​​is a physical quantity that expresses the relationship between the space traveled by an object, the time used for it and its direction. So velocity is the change in position of a body over time:

The mile per hour (mph) is a unit of speed measurement that expresses the number of international miles traveled per hour.

From the definition of speed it can be deduced that the time it takes to travel a certain distance at a constant velocity is:

velocity*time=position

Then, if the position is 10 miles and the velocity is 55 mph:

time=0.1818 hours

If 1 hour is 60 minutes, the time can be expressed as:

time=0.1818 hours*60 minutes= 10.90 minutes

The position is now constant at 10 miles, but the speed is 60 mph. So the time it takes to travel that distance at that speed is:

time=0.166 hours

If 1 hour is 60 minutes, the time can be expressed as:

time=0.166 hours*60 minutes= 10 minutes

To calculate the time you will save, the subtraction of both times obtained is performed:

10.9 minutes - 10 minutes= 0.9 minutes

If 1 minute is 60 seconds, the time can be expressed as:

0.9 minutes*60 seconds= 54 seconds

The time saved on a ten mile trip by traveling at 60 mph instead of 55 mph is 54 seconds

Time = Distance/Rate

for 60 mph

Time = 10 miles/60 mph

= 0.1666 * 60 minutes = 10 minutes

for 55 mph

Time = 10 miles/55 mph

= 0.181818 * 60 minutes = 10.90 minutes

In the given question, in 28 grams of molecule 0.636 moles are present.

A mole is the amount of a substance which comprises exactly 'elementary entities' of that substance.

To find the number of moles in 28 grams of , we first need to determine the molar mass of .

Molar mass of = 12.01 g/mol (carbon) + 2(16.00 g/mol) (oxygen)

= 44.01 g/mol

Now that we know the molar mass of , we can use the following formula to calculate the number of moles:

= 0.636 mol

Therefore, there are 0.636 moles in 28 grams of .

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