UC知道高手进来做到物理求摩擦做工的题
来源：百度知道 编辑：UC知道 时间：2024/05/19 01:55:11
A uniform board of length and mass lies near a boundary that separates two regions. In region 1, the coefficient of kinetic friction between the board and the surface is u1, and in region 2, the coefficient is u2. The positive direction is shown in the figure.
Because the board is very thin and long, we can suppose that N is well-distributed on the surface of the board.
Owning to the symmetry, it can easily come out that
W(f)=-(u1+u2)mgL
If you are still worried about the result, you can do the integral to the following formula: -u1*mg(L-x)/L*dx-u2*mgx/L*dx, from 0 to L.
老大，不是说物理题吗，我怎么看都是英文题啊