The body began to move from a point -3m. After 5 seconds of observation, it was at the point 7m.

The body began to move from a point -3m. After 5 seconds of observation, it was at the point 7m. What is the equation for this motion?

Let us write down the general form of the equation of motion of the body depending on the time t: s = x (t) = x0 + v * t.

s = x (0) = x0 = v * t. For our problem at t = 0, x0 = 3 (m).

at t = 5 s, x (5) = 7 (m). x = x0 + v * t = 3 + 5 * v = 7 (m).

From here you can find the speed v = (7m – 3m) / 5 s = 4/5 m / s = 0.8 m / s.

Assuming that the motion is uniform, with the same speed, the equation has the following form:

x = 3 + 0.8 * t. At t = 0, x0 = 3 (m), at t = 5 s, x (5) = 3 + 5s * 0.8 (m / s) = 3 m + 4 m = 7 (m). The equation is found correctly.