Скачать или смотреть SPH3U 3.06: Newton's 2nd Law Lab (Using PASCO smart pulley)

Purpose:
To study the different aspects of Newton’s second law

Materials:
[ ] Three 1.0-kg masses [ ] Two 200-g masses [ ] One 100-g mass
[ ] Cart (m = ________ kg) [ ] PASCO Smart Pulley [ ] Five Wooden Dowel Bollards

Procedure:
1. Measure the mass of the cart and of the six masses.
2. Attach a PASCO smart pulley to the edge of a level plank. Protect the pulley with wooden dowel bollards. Tie a string to one end of the cart. Make sure that the string is no longer than the height of the worktable.

Part A: Net Force vs. Acceleration (keeping total mass of the system constant)
3. Put two 200 g objects on top of the cart. Hang a 100 g object from the string, and place the string over the pulley.
4. Let go of the cart and use sparkvue to plot a velocity-time graph (see video). Measure its slope for acceleration (a1).
5. Swap the hanging 100 g mass with a 200 g mass and repeat v-t capture. Find the new acceleration (a2).
6. Rearrange for a 300 g handing mass for (a3) and a 400 g hanging mass for (a4).

Part B: Acceleration vs. Total Mass (keeping net force constant)
7. Hang a 100-g mass on the string and have no additional mass on the cart to capture (a5)
8. Add a 1.0 kg object to the top of the cart to find (a6). Add an additional 1.0 kg mass for (a7) and one more for (a8).

Observations:
Include the following table in your report. Include at least one sample calculation for net force.

Part A
1. a. Use a1, a2, a3 & a4 data to plot a graph of net force vs. acceleration. (read CP. 13 for graphing rules)
b. Draw a line of best fit and calculate its slope (show all work, including units.) What does the slope represent?
c. What does this graph indicate about the relationship between net force and acceleration?

Part B
2. a. Use a1, a5~a8 data to plot a graph of acceleration vs. total mass. Draw a smooth curve through the points.
b. What does this graph indicate about the relationship between acceleration and total mass?

3. a. Use the same data from above to plot a graph of acceleration vs. the reciprocal of the total mass (1/m).
b. Draw a line of best fit and calculate its slope (show all work, including units.) What does the slope represent?
c. What does this graph indicate about the relationship between acceleration and inverse-total-mass?

4. Explain (logically) why a graph of Fnet vs. a will pass through the origin when the total mass is constant.
5. Explain (logically) why a graph of a vs. 1/mtotal will pass through the origin when net force is constant.