Secondary III • 2yr.
Can you help me with the following exercise:
“Name the different effects of forces:
- We push on a concrete block
- We pull on a rope
- We twist a rag
- We press on a wooden plank held by two blocks
- We tear a piece of fabric “
Explanation from Alloprof
This Explanation was submitted by a member of the Alloprof team.
Thank you for your question!
First, the question is that you need to assign different types of force effects to the actions described above. These different consequences are as follows: crushing, elongation, torsion, bending and shearing.
Regarding the first example: as the action of pushing on the concrete block very lightly crushes the object, it is a matter of crushing. Admittedly, this is not the best example, but it is the only logical choice compared to the others.
As for the second example: pulling on a rope tends to make it stretch. An extension takes place. The effect is therefore elongation.
Regarding the third example: the rag is subject to two rotational forces in two opposite directions. This is the very definition of twist! The effect is therefore the torsion.
As for the fourth example: the wooden board is subject to several compressive forces, which cause it to bend in several places. The effect is therefore bending.
As for the fifth example: the piece of cloth tears. Two adjacent forces, parallel, and in opposite directions, are exerted on it. The effect is therefore shear.
In short, the trick is to always make sure that you understand the forces at play, so that you know how to identify the effect of their interactions.
Do not hesitate if you have other questions!