10/03/2016 : Centripetal Force with a Motor

Lab #9: Centripetal Force with a Motor
Name:   Charles Xu,
Partner: Anthony, MichellDate:     10/03/2016



Statement:
In this experiment, we want to find a relationship between θ and ω using a spinning motor.

Theory:
Find the relationship between Force and angular speed. Then using trig to substitute Force to θ with known values.

Summary:
Here is the set up of the Motor

We used the meter stick to measure the height of the spinning rod on the top of the motor to the ground and the length of the string. Then, we measure the distance between horizontal rod and the floor, when the stopper just hits the top of the paper on the rod. According to the data, we could find the distance between two horizontal rods, and calculate the angel θ using tangent. We also measure the time period that the motor spins ten rotation before we setting up the ring stand. 

Data from Measurement

Another step, we use free body diagram to rewrite net force equation in terms of gravity acceleration, radius, θ and ω. 

For the radius in the equation, it equals to R(length of the rod from the center) +L(length of the string)sinθ

Then we input our datas into excel and calculated ω using the equation we found, and compared with the ω calculated from time method.

Conclusion:

By comparing the ω calculated from the equation we found to the ω calculated using time, we could found that these two sets of numbers are very close. Therefore, we could say that the relationship between  θ and ω is the equation we calculated. ω=sqrt(g*tanθ/r).