Hello, I am trying to find the magnitude of the resistance force of an object moving down a slope. The question I was given says: A skateboarder heads down a gentle slope (Θ=5°) at a constant speed of 5m/s. Calculate the magnitude of the resistance force. Using the equation mgSinΘ - ma = R, (g = 9.8, a = 0) I got as far as m0.854 = R, but I need m to find R. Is there another equation to find m (the mass of the object)? Any help would be much appreciated.