Centripetal Force

Purpose: To verify Newton's second law of motion for the case of uniform circular motion.

 Table of Trials and Times

The table above shows the five trails for two different masses for the bob. The radius was the same for both masses. To find the time we spun the bob around in a circle 50 times and that gave us our time. The frequency was found by dividing the revolutions (50) buy the time. The time was different for each trial. To find the velocity it is (2pi*50*radius)/time. To find acceleration, it's just velocity/time. To find force we did the (bob mass*velocity^2)/radius.
Once we did that, we found the hanging mass. To find that we hung weight from the bob. The weight was determined by where the weight leveled out the bob to the radius. After found the hanging mass we could find weight, which is just hanging mass*gravity. Then we found the difference between the weight and the force for each trial. As you can tell, for the first bob mass we have under 6% difference for each. Then for the second bob mass, we have under 6.5% difference.

This is the force diagram for the spring. The spring is what the bob is connected to. There are only two forces acting on it. The force of static friction and the force of tension. The forces are equal.

This is the diagram for the hanging weight that held the bob in place at the radius. There are two forces acting on it. The force of tension and the force of gravity. These two forces are equal.















Conclusion: I learned that the hanging weight should be the objective of the force that we found. For sources of error, we could have timed things wrong, measured things wrong, or any other possible human error. To improve we could do more trials and take the best five. When adding mass to the hanging bob, the centripetal force stays the same, but the radius the bob is at changes.