14th Journal Entry
9-13-10
Today, I (Tristan) made a force diagram of Newton's First Law. We also did 3 tests on a straight track in the hallway. The mass of our car is 318 grams and the average of our accelerations is: - 2.34, so our average force is 745.18N.
This is our information:
All of the averages are: Ti = 1.89 seconds, Tf = 8.66 seconds, Vi = 8.12 m/s, Vf = 1.31 m/s, A = - 2.34, F = 744.12, and M = 318.
| Test | Time Intial | Time Final | Velocity Initial | Velocity Final | Acceleration | Distance Traveled |
| 1 | 1.09 | 4.10 | 3.37 | 0.85 | -0.61 | 3m 67cm |
| 2 | 0.5 | 1.47 | 3.10 | 1.35 | -1.19 | 1m 99cm |
| 3 | 0.3 | 3.09 | 17.9 | 1.74 | -5.23 | 5m 37cm |
Newton's First Law states that an object in motion stays in motion until an outside force acts upon it and a still object stays still until an outside force acts upon it. For us, the outside force acting upon our car is the spring and what is stopping our car is the friction on the ground. This is the force diagram representing that:
Our lessons in math while doing this project are absolute value, number sense, and scientific notation. For backwards day tomorrow we will use absolute value to show that even though we went backwards, we still went a certain distance from the starting point, and by using absolute value we simply change the negative into positive to represent this. When multiplying or dividing a number by a decimal, the effect is reversed from the usual effect of growing with multiplication and shrinking with division to the shrinking with multiplication and growing with division (4 times .5 = 2, 4/.5=8, -4 times .5 is -2, -4/.5 is -8) This is because when you divide by a decimal, it would be cut into pieces smaller than whole numbers, making the total "area" of the number larger. With multiplication, the "area" of the number is decreased because the numbers of area “squares” are increased, but they are much smaller and therefore take up less area. With long numbers, sometimes it is faster to write in scientific notation than standard notation. The difference between them is: one has a single digit followed by a sequence of decimals multiplied by 10 to the (however many digits slid) power (10*4 times 6.784502759 instead of 67845.02759). This is useful for numbers like 10,000,000,000,000,000,000,000,000,000,000,000,000 or .000000000000000000000000000000000000000000000000000001, bringing them down to around 10 digits.
~Tristan and Tanner