# On a straight-line highway, they move evenly: a bus – to the right at a speed of 20 m / s, a car – to the left

**On a straight-line highway, they move evenly: a bus – to the right at a speed of 20 m / s, a car – to the left at a speed of 15 m / s, and a motorcyclist – to the left at a speed of 10 m / s. The coordinates of these crews at the start of observation are equal to 500, 200 and -300 m, respectively. Write their equations of motion. Find: at what point in time the bus passed the tree.**

x10 = 500 m.

V1 = 20 m / s.

x20 = 200 m.

V2 = -15 m / s.

x30 = – 200 m.

V3 = – 10 m / s.

With uniform rectilinear motion, the coordinate of the body changes according to the law x (t) = x0 + V * t, where x0 is the initial coordinate of the body, V is the speed of uniform motion.

If the body moves to the right, in the direction of the OX coordinate axis, then the speed has a “+” sign.

If the body moves to the left, in the opposite direction of the OX coordinate axis, then the velocity has a “-” sign.

For the dependence x1 (t) = 500 + 20 * t, the initial coordinate is x10 = 500 m, the speed of movement is V1 = 20 m / s. A speed with a “+” sign means that the bus is moving to the right, along the OX axis.

For the dependence x2 (t) = 200 – 15 * t, the initial coordinate is x20 = 200, the speed of movement is V2 = -15 m / s.

The “-” sign means that the car is moving in the opposite direction to the direction of the OX axis.

For the dependence x3 (t) = -200 – 10 * t, the initial coordinate is x30 = -200, the speed of movement is V2 = -10 m / s.

The “-” sign means that the motorcycle is moving in the opposite direction to the OX axis direction.