The equation of motion of the body has the form: x (t) = 60-5t2. Determine the coordinate of the body at time 3s.

The problem statement says that the equation of motion of a body has the following form: x (t) = 60 – 5 ∙ t². Comparing it with the general form of the equation of the dependence of the coordinates of a body on time, moving uniformly and rectilinearly: x (t) = хо + vо ∙ t + а ∙ t² / 2, we obtain that the body at the beginning of movement had a coordinate хо = 60 m, the initial velocity vо = 0 m / s and acceleration а = 2 ∙ (- 5) = – 10 m / s², that is, since the acceleration is negative, the body makes a backward motion, and at time t = 3 seconds it will have the coordinate x ( 3) = 60 – 5 ∙ 3² = 15 (meters).
Answer: the coordinate of the body in 3 seconds will be 15 meters.