GRED 566
Forces Investigation
Part 1
1) Push the end of a rubber band up through the large hole in the 12” ruler, (the hole nearest the 12”
side) and stick the other end through the loop. Pull snugly.
2) Weigh the block of wood and record the weight on the chart below under “Mass”.
3) Cut a piece of string approximately 18” long. Tie one end of the string to the rubber band and the
other to the screw eye in the block of wood.
4) Place the ruler flat on the table so that the numbers face up and the string runs the length of the
ruler. Pull on the end of the ruler using a slow, even motion and, once the block starts moving, note
where the knot of the string attached to the rubber band is on the centimeter scale. Record this number
on the chart below under “Force Required”
5) Repeat this procedure for first two and then three blocks of wood, recording both the mass of the
objects and the force required to move them.
6) Graph your results on the supplied graph. Draw a line to connect the points. What is the shape of the
line?
7) Using weights and varying the number of blocks, repeat the same tests for several different masses.
Record the results below and then add these data to your graph. How close are these points to your
original line?
Mass Force Required
8) Discuss with your group the following question: what is the relationship between the mass of an
object and the force required to move it? Can you make predictions about masses you haven’t tested
yet? If so, how? Record your answer on a separate sheet of paper. (You can use the back of your graph.)
