I believe the answer is B. Here is an example of weighing by difference and why it is a good method. Let's assume we know the mass of can accurately as 10g and a tennis ball accurately as 5 g.
Now we use a scale in which we can't adjust the zero. Let's suppose at rest and with nothing on the scale the reading is 10g.
So we put the empty can on and it will now show 20g
We add the tennis ball and it will read 25g
Difference between 25-20 = 5g which is the weight of the ball by itself and the original setting of the scale has nothing to do with it.
You could have done it a different way but that wasn't one of the choices. If the scale shows 10 g with nothing on it it will weigh 15 with a tennis ball on it and the difference is 10-5 = 5g for the ball by itself.
A student is assigned the task of measuring the mass of one tennis ball using a scale for which the zero adjustment on the balance is not working. The student is given three balls and the can in which they were packaged. Which of the following strategies will provide the best determination of the correct mass?
A. Weigh each ball separately and average the results.
B. Weigh the empty can; weigh the can with a ball in it; and compute the difference between the two.
C. Weigh the three balls together and divide by three.
D. Weigh each ball separately, adjusting the beam weights from below first and then from above. Then, average the results.
I thin k it is D. need help
2 answers
Weight the empty can, weight the can with ball in it, and compute the difference between the two.
3 answers