The bar being on the horizontal surface of the table was told a speed of 4m / s. Under the action of friction forces

The bar being on the horizontal surface of the table was told a speed of 4m / s. Under the action of friction forces, the bar moves with an acceleration of 1 m / s2. What is the distance traveled by the bar in 5s

Since the bar on the horizontal surface of the table was told the speed vo = 4m / s, the distance traveled S during uniformly accelerated motion can be found by the formula: S = vo • t + (a • t ^ 2): 2, where, under the action of friction forces, the bar moves with an acceleration of 1 m / s2, which means a = – 1 m / s2. Acceleration has a minus sign because it is caused by a force directed against the movement. To find the path traversed by the bar in t = 5s, substitute the values ​​of physical quantities in the formula and perform calculations: S = 4m / s • 5s + (- 1 m / s2) • 5s • 5s: 2; S = 7.5 m.
Answer: the path covered by the bar S = 7.5 m.