Notes, Cautions, and Basic Measurement,

1. Remark:

   It is better to use that gravitational constant, g= 9.80´10²(cm/sec²).

   We use two unit systems in physics, SI unit system, or so-called MKS system, and CGS unit system.

   "MKS" means "meter", "kilogram", and "second." Hence, the SI unit of force is exactly kg-m/sec². We call it "Newton".

   "CGS" means "cm", "gram", and "second." Therefore, the CGS unit of force would have to be g-cm/sec². People use to call it "dyne".

2. Weigh your spring.



OBJECT	Mass, unit:(   )
MSpring
mPlastic Plate
mHanger
Every Metal Mass




3. Make sure that your photogate is functional.
4. Let the smaller end of your spring upper.

1. Please offer five measurements of five different masses at least.

Choose at least 5 rows in the following data table. And mark those rows.



	Added Mass, including the hanger, m, unit: (   )	Added Force, F=mg, unit: (   )	Position, xf, unit: (   )	Displacement, Dx = xf - xi, unit: (   )
C	0.0	0.0	xi=	0.0
C	mHanger=
	350




2. Recommend you that set the initial position at 100 or 110 roughly.
3. You do not have to print out any table of data here, instead of what the lab manual is asking here.
4. The SIMILAR QUESTION:
   • Give me the plot of "F versus Dx". (0.5 POINT)
   • From the above "F versus Dx" graph, point out the experimental "spring constant k of Hooke's law." (0.5 POINT)
   • From the information of the above "F versus Dx" graph, please point out which one could indicate the fitness of your measurement. (0.5 POINT)
   • Please write down the unit of "the spring constant k of Hooke's law." (0.5 POINT)

1. Always let your spring oscillate vertically.
2. Recommend you that use the same spring constant k as in Procedure - Hooke's LAW.
3. Recommend you that adjust the moveable clamp only. Try to keep the photogate clamp lower and not to change it.
4. Recommend you that wait until 15-18 periods have been recorded.
5. Recommend you that keep the same number of periods every time.
6. Remove the maximum, minimum or any obviously bad points.
7. For a massless spring, we have: T = .




	Added Mass, including the hanger and plastic plate, m, unit: (   )	Time Period, T with SDOM, unit: (   )
C	mPlastic Plate + mHanger=		±
			±
			±
			±
			±




8. By filling out the following data table, see how well you have measured!

9. Print out GRAPH "m versus T²."

10. For a massless spring, T = . We will have m= (k/4p ²)(T²) + 0, as Y= MX + B. Treat your spring as a massless one and fill out the following table.

11. For a massive spring, T = . We will have m = (k/4p ²)(T²) - , as Y= MX + B. Treat your spring as a massive one then fill out the folloing data table.




Graph "m versus T2"	Slope, unit: (      )	a massless spring y-Intercept, unit: (      )	a massive spring y-Intercept, unit: (      )	Regression Coefficient
Theoretical	k/(4p 2) =	0	-=	1
Measured
%error	%	N.A.	%	%




12. Print out GRAPH " versus T²."

13. THE SIMILAR QUESTION regarding the last question of the lab in the lab manual:

    Now, based on your GRAPH " versus T²",

    • (0.5) Compare your y-intercept, B, with your m_Hanger. Is the y-intercept, B, on that graph negligible?

    • (0.5) What is the unit of the y-intercept, B, on that graph?

14. THE ADDITIONAL QUESTION regarding the time period formula:

For a massless spring, we have: T = .

For a massive spring, we have: T = = [1 + ()/m]^1/2.

• (0.5) Now, assuming that the added mass, m, is equal to . i.e. m @, in order to calculate the time period, T, which formula should we apply? why?

• (0.5) Now, assuming that the added mass, m, is much smaller than , in order to calculate the time period, T, which formula should we apply? why?

|Main Menu Page| Lab 2 of 2LC|

| Lab 1 of 40B|Main Menu Page| Lab 3 of 40B|