LAB: LEVERS 1

HYPOTHESIS: If I increase the length of effort arm, then the mechanical advantage will … (Q1)

MATERIALS: 1 ruler 20 pennies 2 hex pencils to use as fulcrum

PROCEDURE: Part I

  1. Set up your fulcrum and lever: The two pencils should form your fulcrum. Set up the ruler so that the 1cm mark is on your left and the 30 cm is on your right. Place the fulcrum approximately at the 15 cm mark until the lever is balanced.

(1cm) (30 cm)

  1. Put an Effort Force of pennies (starting with 1) at the left most portion of the ruler. Put the pennies as close as possible to the end of the lever. Be careful that the fulcrum stays in place. Record your Effort Force in the table below.
  1. Determine the Load Force by putting pennies at the 30 cm side of the lever in an attempt to balance out the lever. Keep the pennies as close as possible to the end and be careful that the fulcrum stays in place. Record the number of pennies you needed to lift the load and balance the lever
  1. Repeat the above steps. For trial two use 2 pennies for the load. For trial three use 3 pennies for the load. Record your data in the table above.

DATA TABLE #1

Trial Number / Fulcrum at / Number of Pennies
Effort Force / Number of Pennies
of Load Force
1 / 15 cm mark
2 / 15 cm mark
3 / 15 cm mark

PART II

  1. Set up your lever EXACTLY as described above. Put an effort force of 2 pennies at the left most portion of the ruler.
  1. Determine how much load your effort force of 2 pennies can liftby placing pennies at the 30 cm side of the lever in an attempt to balance out the lever. Record your values in Table 2 below.
  1. Also record the length of the effort arm, which is the length (starting on the effort side) from the end of the rules to the fulcrum.
  1. Repeat the above procedure a second time but this time place the fulcrum at the 12.5 cm mark of the ruler. Record all results in the table below.
  1. Place the fulcrum at the 10 cm mark of the ruler and repeat your experiment again. Recordall results in the data table below.

DATA TABLE #2

Trial Number / Fulcrum at / Length of Effort Arm / Number of Pennies Effort Force / Number of Pennies Load Force
1 / 15 cm mark / 2
2 / 12.5 cm mark / 2
3 / 10 cm mark / 2

ANALYSIS

  1. Graph Table 1. Label the x-axis with the load and the y-axis with the effort.
  1. What type of relationship is plotted on your graph? What happens to the y-value as the x-value increases?
  1. Predict how much effort force it would require to lift a load of 10 pennies if the fulcrum is centered in the middle of the lever?
  1. Graph Table 2. Graph Length of Effort Arm vs. Load Force.
  1. Predict how many pennies of load one might be able to lift if an effort force of 2 pennies is used and the fulcrum is at the 7.5 cm mark?
  1. How is the mechanical advantage of a lever increased?
  1. Is it possible for a person weighing only 100 pounds to lift an object weighting 1000 pounds? Explain.

CONCLUSION:

Answer your hypothesis and be sure to cite your data in the 5 sentence (minimum) conclusion. Please reference effort arm and mechanical advantage in your answer.