Body motion equation: x = 5 + 4t-2t ^ 2. Is the body speed equal to zero at the moment of time? 1) 1 second from the origin

Body motion equation: x = 5 + 4t-2t ^ 2. Is the body speed equal to zero at the moment of time? 1) 1 second from the origin 2) 2 seconds from the origin 3) 3 seconds from the origin 4) 4 seconds from the origin

Given:

x (t) = 5 + 4 * t – 2 * t ^ 2 – the equation of body motion.

v = 0 m / s.

It is required to determine t (second) – at what point in time the speed of the body is equal to zero.

Let us find the equation for the dependence of the speed on time by fulfilling the first-degree derivative of the equation of motion

v (t) = (5 + 4 * t – 2 * t ^ 2) ’= 4 – 4 * t.

Then:

v = 4 – 4 * t;

0 = 4 – 4 * t;

4 * t = 4;

t = 4/4 = 1 second.

Answer: the speed of the body will be equal to zero 1 second after the start of movement