Purpose
Measure changing speed of an object as it rolls down an incline, and graphically analyze its acceleration.
Concept
An object whose velocity is changing is said to be accelerating.
The average acceleration (a) is equal to the change in velocity divided by the elapsed time.
Materials
stopwatch; meter stick; masking tape; inclined ramp; books; cart.
Procedure Part A - Low Incline
1. Set one end of an inclined ramp on a few books so that the cart will roll down on its own.
2. Mark 4 (20 cm) intervals on the ramp with masking tape.
3. Measure the time it takes the cart to travel from point A to point B and record below.
4. Measure the time it takes the cart to travel from point B to C and record below
5. Measure the time it takes the cart to travel from point C to D and record below.
6. Calculate the average speed of the cart in each interval.
7. Calculate the average acceleration by dividing the change in speed by the change in time.
Part B - Higher Incline
1. Repeat the experiment with the ramp at a higher angle.
Observations and Data: Part A - Low Incline
Distance Interval
Time (s)
Total Time (s)
Speed (m/s)
Acceleration (m/s^2)
0.0 to 0.20
0.20 to 0.40
0.40 to 0.60
0.60 to 0.80
Part B - Higher Incline
Distance Interval
Time (s)
Total Time (s)
Speed (m/s)
Acceleration (m/s^2)
0.0 to 0.20
0.20 to 0.40
0.40 to 0.60
0.60 to 0.80
Analysis
Make a graph of distance traveled (vertical axis) versus total time for part A and B.
1. Describe the slope of the distance versus total time graph for part A and B. Does the slope change or stay constant? Explain.
2. Make a graph of speed versus total time for part A and B. Does the slope change or stay constant? Explain.
Application
Starting from rest, if a car accelerates at 0.90 m/s^2, how fast would be moving after 6.0 seconds? How much distance would it cover in the last second?