Ramps Physical Lab

Purpose

This lab explores the forces acting on an object that is on a ramp and how the sum of those forces is related to the acceleration of the object down the ramp.

Required Materials

A smooth surface that you can tilt. Try to get something at least 0.500m long.

Ruler, meter stick or tape measure

A small block (domino, wood, small book, etc.)

Aluminum foil cut to the size of one of the blocks (slightly longer to allow it to wrap around to the top of the block for taping it is place)

Sandpaper cut to the size of one of the blocks (slightly longer to allow it to wrap around to the top of the block for taping it is place)

Tape

Procedure

Static Friction:

1. Set one of your blocks on the smooth surface.
2. Slowly tilt the smooth surface until the block just begins to slide. You may have to try a few times to get the exact point.
3. We will assume that this is the point where the parallel component of the weight equals the force of friction.
4. Carefully measure the rise and the run of the triangle formed by your smooth surface at this angle.
5. Enter this data into the data table I on the submission form.
6. Calculate the angle using the law of tangents.
7. Repeat 2 more times and record.
8. Draw a free body diagram for the object on the slope at the moment it begins to move. Put this drawing in the area provided on the submission form.
9. Write the second law equation in the perpendicular axis in the area provided on the submission form. A second law equation is in the form F=ma. Be sure to include all the forces in the perpendicular axis and to give an equation in terms of the variables. For example, mg instead of Weight.
10. 10.Remember in the perpendicular axis there would be no acceleration so you can set ma=0.
11. 11.Write the second law equation in the parallel axis. When the object first starts to slide, we will assume that a=0 also. In reality, this occurs right before it starts to slide.
12. 12.Using the equation in the parallel axis derive an equation to determine the coefficient of static friction (the assumption is the force of friction has reached its maximum value at the moment the object first begins to slide). The term "derive," as used by AP means that you must show the steps in developing your final equation.
13. 13.The equation should only have variables you have measured in it when you are done. Note that we have not measured the mass of your object.
14. 14.Use your equation to calculate the coefficient of friction in each trial. Show a sample of your calculation in the area provided on the submission form.
15. 15.Repeat the experiment with the block wrapped in foil and the block warped in sandpaper and record your values in data table II and data table III respectively.
16. 16.Calculate the coefficient of static friction in each case.

Kinetic Friction

1. 17.Remove the sandpaper from the block and return it to the top of the ramp.
2. 18.Adjust the angle of the ramp so that the block is sliding down the ramp at a constant velocity.
3. 19.This will be your best guess. It should be a smaller angle than for static friction.
4. 20.Calculate the angle of the slope that results in a constant velocity.
5. 21.Repeat 2 more times and record in data table IV.
6. 22.Write the second law equation in the parallel axis.
7. 23.Solve for the coefficient of kinetic friction. Be sure to show a sample of your calculations in the area provided.

Kinetic Friction - Constant Acceleration

1. 24.Set the incline so that the angle is 10.0o higher than the angle determined for static friction. Record this angle.
2. 25.Place the block at the top of the incline and use a piece of tape or marker to indicate the front edge of the block.
3. 26.Measure from the front edge of the block to the bottom of the incline and record this as the length in data table V.
4. 27.Release the block and measure the time it takes to get to the bottom of the incline.
5. 28.Repeat 2 more times and record your data in data table V.
6. 29.Calculate the average acceleration for the block in each trial using a kinematic equation.
7. 30.You know the initial velocity of the block is 0, you have the measured length, and the time. Show a sample of your work in the area provided.
8. 31.Write the second law equation for the parallel axis of the slope. Remember that this time there will be an acceleration value.
9. 32.Using average value for the coefficient of kinetic friction in data table IV, solve for the acceleration down the slope. Show a sample of your work.

Questions - answer the questions found on the submission form.

Conclusion - a conclusion using the criteria given to you by your teacher( I can do this on my own) but feel free to give an example

Ramps Physical Lab

Data Table I Coefficient of Static Friction (12 Points)

Trial	Rise (m)	Run (m)	Angle (o)	Coefficient
Trial 1			10o
Trial 2			10o
Trial 3			10o
			Average

Draw a free body diagram for the object on the slope at the moment it begins to move. (3 Points)

Write the second law equation in the perpendicular axis. (3 Points)

Write the second law equation in the parallel axis. (3 Points)

Derived equation to determine the coefficient of static friction (4 Points)

Sample Calculation for coefficient of static friction (4 Points)

Data Table II Coefficient of Static Friction with Aluminum (7 Points)

Trial	Rise (m)	Run (m)	Angle (o)	Coefficient
Trial 1			10o
Trial 2			10o
Trial 3			10o
			Average

Data Table III Coefficient of Static Friction with Sandpaper (7 Points)

Trial	Rise (m)	Run (m)	Angle (o)	Coefficient
Trial 1
Trial 2
Trial 3
			Average

Data Table IV Coefficient of Kinetic Friction (10 Points)

Trial	Rise (m)	Run (m)	Angle (o)	Coefficient
Trial 1
Trial 2
Trial 3
			Average

Write the second law equation in the parallel axis. (3 Points)

Solve for the coefficient of static friction. Be sure to show a sample of your calculations. (4 Points)

Data Table V Coefficient and Accelerated Motion (6 Points)

Trial	Rise (m)	Run (m)	Length (m)	Angle (o)	Time
Trial 1
Trial 2
Trial 3

Sample Calculation for Average Acceleration Using Kinematics (4 Points)

Write the second law equation for the parallel axis of the slope. (4 Points)

Using your value for the coefficient of kinetic friction solve for the acceleration down the slope. Show a sample of your work. (4 Points)

Data Table VI Calculated Acceleration Values (6 Points)

Trial	Kinematic Acceleration (m/s2)	2nd Law Acceleration (m/s2)
Trial 1
Trial 2
Trial 3

Questions (3 Points Each)

1. For an object placed on a frictionless ramp, what is the equation for the normal force?
2. If an object is placed on a frictionless ramp, what is the equation for the acceleration of the object down the ramp?

Conclusion (10 Points)

help please