The dependence of the x-coordinate of the body on time t has the form: x = 1 + 2t + 3t ^ 2, the projection

The dependence of the x-coordinate of the body on time t has the form: x = 1 + 2t + 3t ^ 2, the projection of the body’s velocity on the OX axis at time t = 3 with this motion is

By definition of speed: v (t) = (x (t)) ‘. Then:

v (t) = (1 + 2t + 3t ^ 2) ‘= 2 + 6t.

We substitute t = 3 into the resulting formula:

v (3) = 2 + 6 * 3 = 20 m / s.