3.2 Instantaneous Velocity and Speed

Differentiating position to get velocity at a single instant, and why speed is the magnitude that discards direction.

University Physics Volume 1, 3.2 Instantaneous Velocity and Speed

Status

FlagsLoading your progress…

4 exercises

3.2 Exercise 1

The position of an object as a function of time is $x \left(t\right) = \left(– 3 \text{m}/\text{s}^{2}\right) t^{2}$ . (a) What is the velocity of the object as a function of time? (b) Is the velocity ever positive? (c) What are the velocity and speed at t = 1.0 s?

2.5

3.2 Exercise 2

There is a distinction between average speed and the magnitude of average velocity. Give an example that illustrates the difference between these two quantities.

2.5

3.2 Exercise 4

If you divide the total distance traveled on a car trip (as determined by the odometer) by the elapsed time of the trip, are you calculating average speed or magnitude of average velocity? Under what circumstances are these two quantities the same?

2.5

3.2 Exercise 11

A particle moves along the x-axis according to $x \left(t\right) = 10 t - 2 t^{2} \text{m}$ . (a) What is the instantaneous velocity at t = 2 s and t = 3 s? (b) What is the instantaneous speed at these times? (c) What is the average velocity between t = 2 s and t = 3 s?

2.5