Answer:
1. 15m/s
2. 10m/s
3. 70m/s
Explanation:
Average velocity and average speed
Before turning our attention to problems involving non-constant acceleration and using calculus, we consider the concept of average velocity. We will look at examples involving motion with constant acceleration.
Average velocity
We return to the example of the stone being launched vertically upwards from ground level with an initial velocity of 30 m/s. The acceleration is taken as −10 m/s2. We found that the stone's velocity is 0 m/s after three seconds, when it is at a height of 45 metres. The average velocity for the first three seconds of motion is
x(3)−x(0)3−0=453=15 m/s.
This can be illustrated on the position–time graph by the chord from the origin to the point (3,45). The gradient of this chord is 15.
