HOOKES LAW WORK SHEET

HOOKE’S LAW

PROCEDURE

1.     Suspend a spring and a weight pan from the short rod as shown in the illustration.

2.     Place a meter stick along the long metal rod so that the end marked 0 cm is toward the ceiling.  Use a rubber band to hold the meter stick in place as shown.

3.     Read the position of the bottom of the weight pan by looking at the markings on the meter stick.  This is the reading with no load on the pan.  Record this reading on the data sheet.

4.     Place a 150g mass on the pan and read and record the new position of the pan.  Also record the mass and calculate the force it causes on the spring.

5.     Mass and Force are two separate concepts in Physics.  The force, which we are concerned with in this experiment, is the force of gravity acting on the added mass.  This force is called weight (NOTE: MASS AND WEIGHT ARE NOT THE SAME QUANTITY).  In order to calculate the weight from the mass we will use Newton’s second law.

                                                                     F= Mass  x  gravity

(Use g = 10 m/s² ; then the force of the spring (weight) is m * g or m * 10 m/s².)

6.     Subtract the value of the position of the pan with no load from the position found in Step 4.  The difference is the elongation of the spring.  Record this elongation.

7.     Place additional masses in 50-gram increments on the pan and record the new positions.  Calculate and record the force caused by the total mass on the pan.  Also calculate and record the elongation of the spring.

8.     On a sheet of graph paper,  plot a graph of force vs. elongation.  This means on the x-axis you plot DX, and on the y-axis you plot the weight on the spring.

      DATA SHEET

Name:                                                 

Section:                                               

Elastic Spring

Reading with no load                    (cm)

Mass (g)	Mass on spring (kg)	Force on spring (N)	Reading with load (cm)	Elongation of spring (cm)
0	0	0		0
50
100
150
200
250
300
350
400

QUESTIONS

1)     What is the relationship between the elongation of the spring and the weight attached to the spring?  How does your graph support or refute your answer?

2)     What is the spring constant for your spring?

3)     Looking at your graph for the spring, what do you predict to be the elongation of your spring when loaded with a weight of 0.2, 2.0, and 4.0 newtons?