Materials-
Wooden block
Spring Scale
Inclined planes
Balances
Calculators
Felt cloth
Aluminum foil
Carpet
Sandpaper
Procedure-
1. Read the lab instructions.
2. Position the incline plane to a 30 degree angle.
3. Measure the mass of the wooden block.
4. Place the mode of friction (felt, aluminum foil, carpet, or sandpaper) on top of the incline plane.
5. Place the wooden block on top of the incline plane on the side closest to the floor.
6. Connect the spring scale to the wooden block and steadily drag the block up the incline plane.
7. Record the initial force and the continuous force of the wooden block in Newtons.
8. Change the mode of friction and repeat steps 3-5 over again.
Data Table-
Friction Material
Sandpaper
Aluminum Foil
Felt
Carpet
Start Force (N)
2.50 N
1.30 N
1.75 N
1.90 N
Continuous Force (N)
2.40 N
1.25 N
1.69 N
1.87 N
Each angle for measurement was 30 degrees on scale 3 and each time we used Block 11 which had a mass of 207 grams or .207 kg.
Diagrams and Calculations-
On an attached PDF
Final Questions-
1. We pulled the block slowly and consistently in order to obtain an accurate and representative measurement. We also pulled at a constant velocity with an acceleration of zero, so the net force of the movement would be zero as well (Fnet=mass x acceleration). Had we pulled the block at a non-uniform velocity, the force required to move the block would have been inconsistent.
2. As the angle of incline becomes more erect (closer to 90 degrees), the magnitude of the gravitational force increases in the x direction and decreases in the y direction. Therefore, it is more difficult to move the object up the slope as the incline increases.
3. It requires less force to slide an object on a frictionless surface than it does to lift an object because when you lift an object, you are directly opposing the maximum force of gravity. When you slide an object up a ramp then the force of gravity is distributed in both the horizontal and vertical direction making it much easier, and being that the ramp is frictionless, we would not have to overcome the friction force. An example of this would be having to lift a boat up and into the bed of a truck or sliding it up a ramp. Sliding it up the ramp would be much easier.
4. The coefficient of static friction and the coefficient of kinetic friction were unequal because the electron clouds of the objects settle and form to fit each other which makes the object need more energy to start moving than it would need if it was already moving because the electron clouds do not have a chance to settle.
5. Two reasonable sources of error for this experiment are that while pulling on the spring scale we had slight acceleration making the net force not equal zero. Also there were imperfections in the materials we used causing the wood to snag which made it appear to need more force to sustain constant motion.