6.11 Elastic Potential Energy

Question 1

What does a lower spring constant mean?

Answer 1

The object is more elastic and easier to stretch

Question 2

What does a higher spring constant mean?

Answer 2

The object is more stiff and harder to stretch

Question 3

How can you measure the extension of a spring? (6)

Answer 3

• Hang your spring from a clamp stand, then measure the spring’s length using the ruler - this is the spring’s original length
• Weigh your masses and add them one at a time to the hook hanging from the spring, so the force on the spring increases.
• After each mass is added, measure the new length of the spring. Then calculate the extension
• Plot a graph of force (weight) against extension using your results and draw a line of best fit
• A straight line of best fit is where the spring obeys Hooke’s law and the gradient = spring constant. If you’ve loaded the spring with enough masses, the graph will start to curve
• Make sure you carry out the experiment safely. You should be standing up so you can get out of the way quickly if the masses fall, and wearing safety goggles to protect your eyes in case the spring snaps

Question 4

What are 2 things you should make sure of in your experiment of investigating hooke’s law?

Answer 4

• When measuring the length of the spring, you should move yourself so the pointer on the hook is at eye level. Otherwise it could look like it is next to a different marking on the ruler.
• You also need to make sure the ruler is exactly vertical to get an accurate measurement and that the spring isn’t moving

Question 5

What is elastic potential energy?

Answer 5

The energy transferred to an object as its stretched

Question 6

What happens to energy when a force deforms an object?

Answer 6

When a force deforms an object, work is done and energy s transferred to the object’s elastic potential energy store. This energy can be recovered when the forces are removed

Question 7

What is the equation for the energy stored in a stretched spring?

Answer 7

energy stored in a stretched spring = 1/2 x spring constant x (extension) squared

Question 8

How can you find the work done or energy transferred to the spring using a force/extension graph?

Answer 8

The work done is equal to the area under your graph. This is true for any object that is deformed linearly. You can find this area by calculating the area of the triangle or by counting squares

Question 9

What is the formula that links force and extension?

Answer 9

F = ke

Question 10

When a spring is stretched, where is energy transferred to?

Answer 10

Elastic potential energy store

Question 11

When a spring is stretched, energy is transferred to its elastic potential energy store. When the spring is released, what is most of that energy transferred to?

Answer 11

Kinetic

Question 12

What does the gradient of the straight part of a graph tell us?

Answer 12

Spring constant

Question 13

What does the area under the curve of a force - extension graph tell us?

Answer 13

Elastic potential energy

Question 14

What does the point where the line goes from straight to curved show us?

Answer 14

The limit of proportionality/elastic limit