How does the weighted cart experiment prove F=MA?
The experiment is the one where there is a cart attacked to a weight by a string and a pulley. Similar to the one here. . When I did it, I had the same amount of weight of the system in every trail eg. Started with six weights on the hanging weight and transffered them one by one onto the cart. Did I do the experiment wrong and how does this experiment prove F=MA?
The experiment is the one where there is a cart attacked to a weight by a string and a pulley. Similar to the one here. . When I did it, I had the same amount of weight of the system in every trail eg. Started with six weights on the hanging weight and transffered them one by one onto the cart. Did I do the experiment wrong and how does this experiment prove F=MA?
1 Answer
You may have either done it incorrectly, or used the wrong values in the equations.
Explanation:
There are several ways to do this experiment. The one indicated in the video looks like they are ADDING Mass to the cart - but NOT taking it off of the pulling weight.
The other is to maintain a constant cart mass and add mass to the pulling weight.
My favorite set-up is the inclined plane, or "soapbox derby", using cars with variable weights. That involves a bit more math due to the angle, but is easier to modify.
In all cases the empirical measurement is the time it takes the cart to traverse the length with different masses - either as the driving force or the object moved. The relationship in the equation does not even depend on the acceleration factor - just the evidence that it is a proportional factor.
Make a plot of "F" (weights on pulley), "m" mass of cart (plus weights, if added) and time "t". The table should show that Force is increased for the same amount of mass, the time decreases as a square root (acceleration).
IF you change BOTH the driving force (pulley weights) AND the cart weight at the same time you are not doing the experiment properly, but you may still be able to use the data if enough of it is collected.
