posted by Physics on .
A brick of mass 1.0 kg slides down an icy roof inclined at 30.0 degrees with respect to the horizontal. (a) If the brick starts from rest, how fast is it moving when it reaches the edge of the roof 2.00 m away? Ignore friction. (b) Redo part (a) if the coefficient of kinetic friction is 10.0
(a) Use conservation of energy. The distance it descends is 2.00 sin 30 = 1.00 meter. Mass will cancel out.
(b) Use conservation of energy again, but subtract the heat loss due to friction work from the energy available for kinetic energy. The coefficient of kinetic friction would not be 10 on an icy roof. You or someone must have copied something wrong. If it were that high, the brick would not move.