QUESTIONS

1. How does increasing the mass of the car change the total energy?

2. How does increasing the mass of the car change the speed of the car at the bottom?

3. Does the car lose a greater percentage of its energy when it has the extra mass or not?

1. Configure the track as shown in Figures 2 and 3. Attach photogates at the top of the hill and on the straight portion at the bottom. Also put the catcher on the end of the straight part to keep the car from going off the end of the track.

2. Place the Mini Car at the top of the hill on the left. Mark on the white board where you start the car. Measure the initial height of the car: Measure from the table to the center of the car.

3. Place the car at the top of the small hill in the center and measure the height of the car.

4. Place the car at the bottom on the flat part of the track and measure the height of the car from the table.

5. Place the car at the top and release it from rest. Use the Smart Timer on Velocity: 2 Gate Mode to measure the speed of the cart at the top of the center hill and at the bottom.

6. Calculate the initial total energy of the car.

7. Calculate the total energy of the car at the top of the center hill.

8. How much energy is lost? Where does it go?

9. Calculate the percent of total energy lost.

10. Calculate the total energy of the car at the bottom. Calculate the percent of the total energy lost between the starting position on the left and the final position on the right.

QUESTIONS

1. Using the speed of the car at the top of the middle hill, calculate the normal force on the car. You will need to estimate the radius of a circle that matches the curvature of the hill by drawing the circle on the white board.

2. How fast would the car have to go to cause the normal force to be zero at the top of the hill? How high would the car have to start to make this happen?

1. Configure the track as shown in Figures 4 and 5. Attach a photogate at the top of the loop. Also put the catcher on the end of the track to keep the car from going off the end of the track.

2. Put a peg in the center of the loop. Place the Mini Car at the top of the loop. Mark on the position of the center of mass of the car on the white board. Measure from the center of the center peg to the center of mass of the car at the top of the loop (see Figure 6).

3. Measure the distance from the center of mass of the car at the top of the loop to the table.

4. Using Conservation of Energy, predict the minimum height from which the car can be released on the left end of the track so the car will just make it completely over the loop.

5. Draw a horizontal line from the top of the circle you drew for the loop to the left part of the track. Measure from this line to mark the starting position calculated in Part 4.

6. Place the center of mass of the car at the marked predicted position and release it from rest.

QUESTIONS

1. Does the car make it over? If not, why not? If so, does it just make it or did you start too high?

2. Once you have determined the release position where the car will make it over the loop, observe and mark the highest position reached on the right side of the track. In theory, where should this position be? How far above or below is this position from the horizontal line drawn in Part 5? Use the loss in height from the starting position to calculate the percent energy lost.