1. a person walks 3 kilometers in an hour, rests for an hour, and then walks 3 more kilometers in another hour. What is the average speed of the person over the three hours?

2. a car travels north for 20 km. The car then travels south for 35 km. If north is taken as the positive direction, what is the displacement of the car?

Hey there!

1. To find the average speed of something, you use the formula d=rt, or distance equals rate (speed) multiplied by time. We can plug what we have into this equation to find the average speed. The distance is 6 km, and the time is three hours.

6=3r

Now we sole

r=2

Therefore, the average speed is 2 km per hour.

2. If we were to put this on a vertical number line, the car would be at -15. Displacement is the change in original position. If it was originally at point 0, it's displacement is 15 km south. Because it says that north is a positive direction, that must mean the south is negative.

Therefore, your answer is -15.

I hope this helps! Have a great day!

1. 2km/h   2. -15km

Explanation:

1. speed=whole distance/time=(3+0+3)/3=2

2. 20-35=-15

the answer is either b or c

when [oh-] is 10-5  m, and [h3o+] is 10-9  m, the poh is 5 and ph is 9. again in both cases the sum of ph and poh is 14. however, the hydrogen ion concentration is not always going to be equal to exactly 1 x 10 raised to a negative number. for example, we skipped over the value of 2.0 x 10-7.