Explain how to find instantaneous velocity and find it for s (t) = - 3 + 4t2 when t = 5 seconds

Velocity is a vector quantity, that's formally defined as the rate of change of position or displacement with time. When stating any vector like the velocity of an object, we talk about direction, as well as magnitude. That's why speed and velocity are different things. Speed is a scalar (a pure number, specified by magnitude, without direction), while velocity is a vector. To put it simply, speed is the magnitude of the velocity. When talking about velocity, we specify it according to some fixed frame of reference and its unit is meters/second. It can be measured in two ways. One is in the form of average velocity, while the other is instantaneous velocity. The formula for the former is as follows.