hey bob,
this question
average force of friction
thanks a lot. i only don't get one part.
Now, set the potential energy of the rubber band (stretched x cm) equal to the work done on friction
why is this equal to work done by friction?
how come we can't use velocity, acceleration method but instead deal with the transfer of energy?
thank you very much bob.
You have no way to MEASURE velocity or acceleration. The simple and direct way is with energy concepts. The energy of the rubber band is disspated in work done on friction.
Why is it equal? Where else could the energy stored in the rubber band go? All movement is stopped.
Hey there!
When trying to calculate the average force of friction, we can approach it in different ways. The method you mentioned involving potential energy and work done on friction is one way to analyze the situation.
In this case, we consider the potential energy stored in the rubber band when it is stretched by x cm. The rubber band, when released, exerts a force on an object, and this force is what opposes the motion due to friction. As the rubber band returns to its unstretched state, this force decreases until it eventually comes to a stop. The work done by friction is what dissipates the energy stored in the rubber band.
Using the concept of energy allows us to understand how the energy stored in the rubber band is transferred to friction. This approach is often easier since it doesn't require direct measurements of velocity or acceleration. It simplifies the analysis by focusing on the transfer and dissipation of energy.
Alternatively, using velocity and acceleration to calculate the average force of friction can be more complex because it involves precise measurements and calculations. Additionally, measuring velocity or acceleration directly can sometimes be challenging or impractical.
By focusing on the transfer of energy and the dissipation of the rubber band's potential energy, we can determine the work done by friction more directly and easily.
I hope this explanation clarifies why we utilize the concept of energy rather than the velocity and acceleration methods. If you have any further questions, feel free to ask!