物理的幾個(gè)英文定律和題目 求翻譯
定律1.the direction of velocity in curvilinear motion is changing with time and the direction of the velocity of a particle at a certain point(or instsnt)is in the tangent direction of the curve at that point.
2. when the direction of the net force a body experiences and the direction of the velocity of the body do not fall in the same straight line, the body is in curvilinear motion.
題目1. if a boat's speed in the still water is 5m/s, and the speed of the water in a river is 3m/s. how can we cross the river in the shortest time? and how about the shortest distance?