# Speed and Radius Lab

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

Manipulated: Radius

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....

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