First, launch the video below. You will be asked to use your knowledge of physics to predict the outcome of an experiment. Then, close the video window and answer the question at right. You can watch the video again at any point.

Suppose we replace the mass in the video with one that is four times heavier. How far from the free end must we place the pivot to keep the meter stick in balance?

a. 50 cm (in the middle)
b. 90 cm (10 cm from the weight)
c. 75 cm (25 cm from the weight)
d. 10 cm
e. 25 cm