Core Practical: Investigating Force & Extension Flashcards
All 7 cards in this deck
In the core practical, how is the extension of the spring found at each load?
Subtract the original (unloaded) length from the new length measured with a metre rule: extension = difference between the two positions.
What are the steps of the core practical to investigate force and extension for a spring?
e.g. adding N weights up to N- Clamp the spring vertically and measure its original length with a metre rule.
- Add a known weight, then measure the new length and calculate extension = new original.
- Repeat for increasing weights and plot force against extension.
In the force–extension core practical, which variable is plotted on which axis (Edexcel convention)?
Force (N) on the vertical axis, extension (m) on the horizontal axis.
Give two ways to reduce measurement error when finding the extension of a spring.
Read the rule at eye level to avoid parallax and use a fixed pointer/marker on the spring; take repeat readings.
How does the shape of a force–extension graph for rubber differ from that for a spring?
Rubber gives a non-linear (curved) graph, and its loading and unloading curves do not pass through the same points; a spring gives a straight line with one line only.
What does the area enclosed between the loading and unloading curves for a stretched rubber band represent?
The difference in energy transferred when loading and unloading — energy transferred to the thermal energy store (dissipated to the surroundings).
True or false? In the force–extension practical you should keep adding weights until the spring no longer returns to its original length.
False. Overloading permanently deforms the spring and ruins the results; stay within the elastic limit.