【单选题】An uniform thin rod OA is pivoted on a frictionless hinge at one end O, as shown in Fig. The rod is held at rest horizontally and then released. When it reaches the vertical position which one is corr...
A.
Angular velocity varies from small to big, angular acceleration remains unchanged;
B.
Both angular velocity and angular acceleration vary from small to big;
C.
Angular velocity varies from small to big, while angular acceleration varies from big to small;
【单选题】According to the FAO, as the demand for organic food and products increases, prices will be lower for organic products than conventional products.
【简答题】A thin rod of finite length L has charge q spread uniformly along it. What is the magnitude E of the electric field at point P where is from the rod d (linear density: l ) ?