# Centripetal Force Lab Report

Topics: Kinematics, Force, Centripetal force Pages: 7 (1348 words) Published: April 11, 2013
Purpose

To be able to understand and verify the relationship centripetal force, mass, velocity, and the radius of orbit for a body that is undergoing centripetal acceleration.

Background Information

An object moving in the same direction is not necessarily undergoing acceleration. If the object changes speed while moving in the same direction there is acceleration (or deceleration). On the other hand, if the object moves at a constant speed in the same direction, there is no acceleration. This does not mean that constant speed always indicates no acceleration, however. An object that moves at a constant speed and changes direction is also experiencing acceleration even though its speed never changes. Both the acceleration produced by changing speed and the acceleration produced by changing direction require a net force. This force that is produced in called the centripetal force and the acceleration that causes a change in direction is called centripetal acceleration.

Centripetal force means “center seeking.” It is the force responsible for keeping an object in circular motion. If there were no centripetal force the object would fly off at a tangent because of Newton’s First Law. This is demonstrated by spinning an object on a string. If the string were to break or be cut, the object would fly out of its circular path at a tangent.

An equation can be used to represent the relationship between centripetal force, mass, velocity, and the radius of the circle. This equation is: [pic]

Equipment and Setup

• Plastic tube
• Nylon cord
• Several rubber stoppers of different sizes
• Hanging masses
• Stopwatch
• Meter stick
• Tape

Setup

Procedural Summary

String a plastic tube on the nylon cord and place a rubber stopper on one end and a hanging mass on the other end. Hold the plastic tube and spin the rubber stopper above the head in a circular path. Use a stopwatch to time how long it takes to make 20 rotations. Change the rubber stopper mass, length of string above the rube (radius), and mass of the hanging mass and repeat to see how these factors affect the results.

Data

| |Trial # |Hanging Mass (g) |Mass of Stopper (g)|Total Time (s) |Radius (m) | |Varying |1 |100 |45.3 |18.72 |0.5 | |Mass | | | | | | | |2 |150 |45.3 |15.31 |0.5 | | |3 |200 |45.3 |14.5 |0.5 | | |4 |250 |45.3 |12.87 |0.5 | | |5 |300 |45.3 |11.25 |0.5 | |Varying |6 |100 |45.3 |17.16 |0.3 | |Radius | | | | | | | |7 |100 |45.3 |17.69 |0.45 | | |8 |100 |45.3 |18.65 |0.6 | | |9 |100 |45.3 |22.94 |0.75 | | |10 |100 |45.3 |23.78 |1 | |Varying |11 |200 |45.2 |14.39 |0.5 | |Stopper | | | | | | | |12 |200 |13.1 |9.04 |0.5 | | |13 |200 |28.4...