To determine the speed of uniform motion, it is necessary to divide a way into time. For the uniformly accelerated movement it is necessary to add the acceleration increased by time to initial speed.
Instruction
1. To determine the speed of uniform motion it is necessary to divide length of the passable way for a while which was required on this way: v=s/t, where: v – it is speed, s is length of the passable way, at is a vremyaprimechaniye. Previously, all units of measure should be given to one system (it is desirable for SI). An example 1 Having dispersed to the maximum speed, the car passed one kilometer in half-minute then slowed down and stopped. Determine the maximum speed of the car. Decision. As after dispersal the car moved at the maximum speed, it under the terms of a task can be considered uniform. Therefore: s=1 of km, t=0.5 min. We give units of measure of time and the passable way to one system (SI): 1 km =1000 m0.5 mines = 30 sekznachit, the maximum speed of the car: 1000/30=100/3=33 1/3 m/s, or approximately: 33.33 m / sotvet: maximum speed of the car: 33.33 m/s.
2. For determination of speed of a body at the uniformly accelerated movement it is necessary to know the initial speed and size of acceleration or other connected parameters. Acceleration can be and negative (in this case it, actually, braking). Speed is equal to initial speed plus the acceleration increased by time. In the form of a formula it registers as follows: v(t) = v (0)+ at, where: v(t) – body speed in timepoint of tv (0) – the initial speed of a tela – size uskoreniyat – time which passed an uskoreniyaprimechaniye.1 from the moment of the beginning. The movement in a straight line is meant. 2. Initial speed as well as acceleration, can be negative concerning the chosen direction.3. Acceleration of gravity usually is accepted equal 9.8 m/s²Пример 2C roofs threw a brick with a speed 1m/page down. In 10 seconds it reached the earth. What brick speed at the time of landing was equal to? Decision. As the direction of initial speed and acceleration of gravity coincide, the Earth's surface will have an equal brick speed: 1+9.8*10=99 m/s. Air resistance in tasks such, as a rule, is not considered.