You stand at the top of a tall building with a stopwatch. you drop a rock off the side of the building, and it takes the rock 1.9 seconds to hit the ground. how fast was the rock going when it hit the ground

18.62m/s

Explanation:

The rate of acceleration that gravity has on an object is 9.8 m/s^2.

In this problem, the object is falling for 1.9 seconds so to solve, you need to plug it into the equation which gives you sp=9.8*1.9.

After multiplying the two numbers, you get an answer of 18.62m/s.

work: w = fd (given)

work done by chet   =50*1 = 50 j

work done by mika =40*2 = 80 j

work done by sara =30*1.5 = 45 j

work done by bill =60*0.5 = 30 j

students in order from the greatest amount of work done to the least is mika> chet> sara> bill

hence option (b) is correct.

hi there!

out of the two, (b) precision would be more reasonable.   however, both a and b could be pretty reasonable.

-awesomerepublic   : )