Physics Lab Hooke’s Law
A. Introduction: Hooke’s Law
Consider a spring with one end fixed:
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When no force acts to stretch or compress it, it has its equilibrium length x0.
To stretch it or compress it requires applying a force to the end:
The strength of the force needed depends on two factors:
One is the “stiffness” of the spring, characterized the spring constant ‘k’. This is
different for different springs. So, force depends on ‘k’.
The second and less obvious factor is this: the more the spring is stretched, the
greater the force needed to stretch it.
In fact, F = kx,
This is Hooke’s law.
B. Objective : determine the spring constant ‘k’ of a spring.
C. Procedure:
1. You must stretch the spring to four different displacements using the
masses provided.
2. Measure x in SI units for each applied force.
3. Make a graph of F vs x, so that the slope will be ‘k’, and determine the
spring constant of your spring
4. Repeat for your other elastic object.
D. Data: all measured and calculated values: Force, x, k
D. Discussion Questions
1) What are the units of ‘k’?
2) Theoretically, is there a minimum (non-zero) force required to
start the stretch of the spring? What does this value correspond to
on your graph of Force vs. x?
3) Which of your objects required more work to stretch to the same
length?
4) How does a spring scale work? How do you think it is
determined what numbers to put on the side?
Physics Lab
Pendulum
A. Objective: Determine the effect of mass and length on the period of a pendulum.
Period –
Mass –
Length –
B. Design a procedure to evaluate the effect of increasing mass
Design a procedure to evaluate the effect of increasing length
C. Data
Effect of mass – constant length
Trial
mass
period
max amplitude
max PE
Effect of length – constant mass
Trial
length
period
max amplitude
max PE
D. Discussion
1. What is the effect of increasing mass on period of the pendulum? Use your data
to support your answer.
2. Is the total mechanical energy of the system affected by increasing the mass?
3. Is more/less/the same work required to place each pendulum into motion in the
mass experiment? Support your answer with a formula.
4. Describe where the pendulum is moving the fastest. Is the speed of the pendulum
affected by the increasing mass? Support your answer.
5. What is the effect of increasing length on the period of the pendulum? Use your
data to support your answer.
6. Is the total mechanical energy of the system altered as the length of the pendulum
is increased? Does it require more/less/the same amount of work to place each
pendulum into motion? Support your answers with formulas.