Topics: Circular motion, Force, Rotation Pages: 3 (459 words) Published: May 16, 2012

Question
For an object moving with uniform circular motion, what relationship exists between the radius of its path and its speed?

Hypothesis
If the radius is increased, I believe that the speed will decrease, giving speed and its radius an inverse relation.

Variables
The variables in this lab are the radius of the circular path, mass of the rubber stopper, mass of the hanging weight, number of revolutions, elapsed time, period, and speed.

Materials and Equipment
See page 245.

Procedure
See page 245.

Mass : 107 g
Time for 20 Spin Revolutions (s)
Radius |Time 1 |Time 2 |Average time (s) |Period (s) |Speed (m/s) | |20cm |7.2 |7.4 |7.3 |0.365 |3.44 | |30cm |6.7 |7.2 |6.95 |0.3475 |5.42 | |40cm |7.4 |7.4 |7.4 |0.37 |6.79 | |50cm |9.4 |8.2 |8.8 |0.44 |7.14 | |60cm |9.6 |8.8 |9.2 |0.46 |8.20 | | Analysis

Variables
Controlled: Mass of hex nuts, number of spins
Responding: Time

The force acting as the centripetal force in this lab is tension, which is caused by gravity. Fg= mg. Fg= 1.05 N. The speed varies with the radius of the string. The larger the radius, the slower the speed. My hypothesis was incorrect. Although the time got longer, the speed also increased making it faster as the radius increased. According to my data, speed and radius have a direct relationship.

Speed and Centripetal Force

Question
What is the relationship between centripetal force and the speed of a mass moving in a horizontal circle?

Hypothesis
If the centripetal force of a mass moving in a horizontal circle is increased, I believe that the speed will also increase, giving speed and centripetal force a direct relationship.

Variables
The variables in this lab are the radius of the circular path, mass of the rubber stopper, mass of the hanging mass, number of revolutions, elapsed time, period, and speed.

Materials and Equipment
See page 257.

Procedure
See page 257....