The piston of a machine exerts a constant force on a ball as it moves horizontally through a distance of 15 cm. You use a motion detector to measure the speed of five different balls as they come off the piston; the data are shown in the table. Use theory to find two quantities that, when graphed, should give a straight line. Then use the graph to find the size of the piston’s force.

Mass (g) _____________ Speed (m/s)

200 ………………………… 9.4

400 ………………………… 6.3

600 ………………………… 5.2

800 ………………………… 4.9

1000 ………………….…… 4.0