First of all, hi! I'm new here. 1. The problem statement, all variables and given/known data Rather than a specific problem, my friend and I are doing an Extended Experimental Investigation on the energy transfer of dominoes for our grade 12 assignment. 2. The attempt at a solution We have approached it using loss of gravitational potential energy (Ug) and then comparing that with rotational kinetic energy determined by the theta: Theta is the angle from the vertical to the point as where it has fallen. Assumptions: Gravitational energy becomes rotational energy. The domino's leading edge that it rotates around does not slide The domino has a toppling point, and its velocity at this toppling point is 0m/s We then aim to compare these two values with experimental data gathered with a camera. Here's what we have done (equation number): To find the gravitational potential energy, we calculated the height of the center of gravity at the toppling point* (1), found Ug at this point, then calculated Ug at the end point in the same method (2). The difference was found, and hence the loss of gravitational energy, which should have been converted into rotational kinetic energy. *The toppling point is when the point of the center of gravity of the domino is outside the vertical of the axis of rotation. I.e, draw a diagonal from the edge the domino is rotating on to the opposite corner (this line will pass through the center of gravity) and when that diagonal line passes vertical, the domino starts to fall due to gravity. If the diagonal is not past the vertical, it will fall back to an upright position. To find the rotational kinetic energy theoretically we did the following: The Domino's velocity is 0 at the toppling point, at which the angle is dependent on the height (3). The acceleration of the domino is not constant, however is can be modeled. As the angle of fall increases (theta), the component of gravity actually affecting the domino increases, hence the acceleration increases(4). Thus by integrating the acceleration, one can find the velocity (i say velocity here, but it is more the speed of the domino) of the domino due to the falling angle (5). Once this velocity is acquired, it was used to find the rotational velocity (omega) (6). Using the mass moment of inertia (7) and the rotational velocity, the rotational energy was found (8). 3. Relevant equations The equations jpeg. Summary Basically, the calculated change in Ug and Ekr does not match and i want to know why!!; they are out by about a factor of 7. I have attached my spreadsheets if you want to look at exact calculations, however, because the formulas derived are dependant on height as well as theta, in the rotational energy spreadsheet columns E, F, G, H, and K are all for the height of 0.05m. The rotational energy calculated is at a theta value of 1.42 i think - Pretty much the last cell in the bottom right.