Objectives:

1. Measuring force and extension of spring from simulation
2. Finding K (spring constant) from graph
3. Apply Hooke's law to solve problems
4. Elastic potential energy

Theory:

1. Hooke's law states that: force is directly proportional to the extension of spring,

F=kx.Where:

= stretching force applied to the spring

= spring constant

= extension of the spring

1. F=kx, is an equation for a straight line where k is the slope of force vs extension graph.
2. The work done by F (Elastic potential energy) is equal to U =.

Where:

U= elastic energy

k= spring constant

x= extension of the spring

Procedure:

Part 1:

1. Go to the simulationhttps://phet.colorado.edu/sims/html/hookes-law/latest/hookes-law_en.html.
2. Choose the first option (intro)
3. Start filling the table provided down below. Do not change the spring constant value, set it as k= 500 N/m throughout the experiment.
4. Keep increasing the force by 20N each time.
5. Calculate the extension of spring using the data recorded in the table.
6. Calculate the Elastic energy.
7. Go to Excel, create a force vs extension of spring graph from the table you filled.
8. Find the spring constant from the graph (slope).
9. Find the percentage error of the spring constant (real value = 500 N/m), (the expected value is the slope of the graph).

Part 2:

1. Questions related to k (spring constant)

Part 3:

1. Solve questions on Elastic energy.

Part 1

1. Fill the table below:

k=500 N /m
Force (N)( y-axis )	Extension(m)(x-axis)	Elastic energy
20 N

Paste the graph:

• Slope (k _exp) =

• Spring constant (k _real) =

• Percentage error %=

Part 2

1. When increasing the spring constant (k) what do you notice:

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1. When decreasing the spring constant (k) what do you notice:

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1. Explain why the formula (F=-kx) is negative in some cases?

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1. A horizontal spring has a spring constant of 80.0 N/m. What force must be applied to the spring to compress it by 4.0 cm?

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1. A spring is stretched 0.50 m and the force was 30000 N. What is the spring constant?

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Part 3

1. A spring with a constant of76 N/mis extended by0.9 m. How much energy is stored in the extended spring?

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1. A toy rocket-launcher contains a spring with a spring constant of 35 N/m. How much must the spring be compressed to store 1.5 J of energy?

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1. A box is connected to a spring is extended to 200mm, and it stored 3578J of energy. Find the force.

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Conclusion:

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