Mentors Note: Posts from a duplicate thread have been merged into this one. Hello, please explain the following in detail. I am a learning assistant (LA) at a major university but am stuck explaining a concept to my students. Does mass have an impact on an inclined plane? A cart with wheels or a block of wood sliding down? I say, no. And, I can mathematically show this. However, my students showed me a Java applet in which a mass is put into a toy truck, and, upon its release off of a ramp, the travels farther! Is this true? When I substantiate my claim, I continually get the masses to cancel. acceleration = g * (-mu_k * cos(theta) + sin(theta) ). (equation 1) simple model, I get mu_k = a/g (equation 2) Where mu_k is the coefficient of kinetic friction. Mass never appears. The students said that on Olympic bobsled on Wikipedia, the claim is that heavier sledders sleigh down faster. On YouTube videos, heavier skate boarders skate down faster. I keep claiming that, using conservation of energy, v = sqrt(2gh) (equation 3). Am I right or are they right? I tutor an entire class of university students and I am angry at myself for getting entangled in something I should know. Thank you.