Q1. What fraction of the power radiated by the sun is intercepted by the planet Mercury? The radius of Mercury is 2.44 x 106 m, and its distance from the sun at the moment is 5.75 x 1010 m. presume that sun radiates uniformly in all directions.
Q2. A 2000 {rm kg} car travelling at a speed of 40 {rm m/s} skids to a halt on wet concrete where f_k = 0.60. How long are the skid marks?