posted by Nikita on .
An object of mass m = 2.7 kg moves with initial speed vinitial = 2.2 m/s, then interacts with its environment, releasing 4.4 J of work. What is the speed of the object after the interaction is completed?
I found KE initially and then subtracted 4.4J and with the new value i recalculated v...but the answer was wrong. So I am not sure what i am doing wrong
If the initial KE you got was 6.53 J, and you subtract 4.4 because of doing work, then the remaining KE is 2.13 J. Convert that back to velocity. It is about 57% of the initial velocity. If you got similar answers and the book says it is wrong, the difference may be in how the answer was rounded off. I would keep three significant figures until the last calculation, and then round the answer off to two figures. I cannot see what you did, or what the "book" answer is, so can't find the source of the discrepancy