When the body moves along the X axis, the coordinate of the body changes according to the law

When the body moves along the X axis, the coordinate of the body changes according to the law: x = 300 + 30t-3t ^ 2. How long does it take for the body to stop?

These problems: the law of motion along the X axis: x = 300 + 30 * t – 3 * t ^ 2.

1) Let’s define the law by which the speed of the body changes: V = x ‘= (300 + 30 * t – 3 * t ^ 2)’ = 0 + 30 * 1 – 3 * 2 * t = 30 – 6 * t.

2) Let’s calculate the time until the body stops V = 0 = 30 – 6 * t, whence 6 * t = 30 and t = 30/6 = 5 s.

Answer: The body will stop in 5 seconds.