# Hypthesis, Materials, Method

Topics: Force, Mass, Classical mechanics Pages: 2 (286 words) Published: May 2, 2013
Hypothesis

If mass is increased, than the friction will also increase because to solve for friction you multiply the coefficient of friction by the normal force and normal force is calculated by the mass x 9.8 (acceleration due to gravity). So therefore the higher the mass the higher your normal force meaning the higher your friction.

Equipment and Supplies List

• String
• Tape
• Newton spring scale
• Desk (wooden surface)
• Rubber
• Masses (0.5kg, 1kg, 1.5kg, 2 kg, 2.5kg)
• Scale
• Scissors

Method

1. Measured the mass of the rubber using a scale.
2. Attached the 10cm string to the rubber using tape.
3. Placed the rubber on the desk and added a 500g mass
4. Attached the spring scale to the string and pulled with an increasing horizontal force until the rubber just started to move. 5. Noted the reading on the scale then recorded it under force of static friction on the observation chart. 6. Repeated steps 3 and 4, two more times then increased the mass by 500g every time. 7. Repeated steps 1-3 but during step 4, pulled the rubber with a constant horizontal force and noted the maximum force while moving at a constant rate. 8. Recorded the maximum force under force of kinetic friction on observation chart. 9. Repeated steps 7 and 8, two more times increased the mass by 500g every time.

Variables

Independent: Mass
Dependent: Force of kinetic and Static friction
Controls: Rubber being pulled, position of mass on rubber, length of string, surface, Newton scale.

Safety Considerations

While doing this lab you must cut the string so be careful while handling scissors. Also be careful of not dropping the weights because they could be heavy.