Physics Problem: Snow sliding off a roof

This is the lecture video for my online course. You can find the whole playlist here.    • Physics 01   A roof has snow on it and is inclined 30 degrees above the horizontal. A block of snow starts 3 meters up the roof, slides down (frictionlessly) and falls off the roof onto the ground. If the edge of the roof is 4 meters above the ground, how far from the house does the snow land?