Which statement best explains the backward motion of the boat as the person moves forward

a: every mass exert a force on every other mass
b: an object at rest tends to stay at rest
c: friction opposes the motion of an object
d: for every action there is an equal and opposite reaction

You encounter a solution that is acidic and you decide to test it by adding a small amount of a strong acid. the ph lowers slightly but is approximately unchanged, and still remains acidic. what can you say about the solution? a. it is a buffer solution. b. it is not a buffer solution it is a strong acid solution. d. the solution has been neutralized. e. the solution has excess acid present

Significant figures are digits read directly from the measuring instrument plus one more digit, which is __ by the observer.

6. using 3 – 4 sentences explain (in your own words) why water expands when it freezes? 7. using your knowledge of colligative properties explain whether sodium chloride or calcium chloride would be a more effective substance to melt the ice on a slick sidewalk. use 3 – 4 sentences in your explanation.