Average Velocity Video Lessons

Concept

# Problem: A particle is at x1 = 3.4 cm when t1 = −5.4 s and is at x2 = 8.0 cm when t2 = 5.6  s .(a) What is its average velocity?(b) Can you calculate its average speed from these data?

###### FREE Expert Solution

We're asked to calculate the average velocity of a particle given a change in position and a change in time.

Recall that the average velocity of an object, ${\stackrel{⇀}{v}}_{avg}$, is related to the change in position (displacement,${∆}\stackrel{⇀}{x}$) over change in time Δt:

$\overline{){\stackrel{\mathbf{⇀}}{\mathbit{v}}}_{\mathbit{a}\mathbit{v}\mathbit{g}}{\mathbf{=}}\frac{\mathbf{∆}\stackrel{\mathbf{⇀}}{\mathbit{x}}}{\mathbf{∆}\mathbit{t}}{\mathbf{=}}\frac{{\mathbit{x}}_{\mathbf{2}}\mathbf{-}{\mathbit{x}}_{\mathbf{1}}}{{\mathbit{t}}_{\mathbf{2}}\mathbf{-}{\mathbit{t}}_{\mathbf{1}}}}$

Velocity is a vector, which means the signs really matter (unlike speed, which is a scalar.)

(a) For the particle in this problem, we're first asked to calculate its average velocity between t1 and t2. We're given that x1 = 3.4 cm, x2 = 8.0 cm, t1 = −5.4 s, and t2 = 5.6 s.

###### Problem Details

A particle is at x1 = 3.4 cm when t1 = −5.4 s and is at x2 = 8.0 cm when t2 = 5.6  s .
(a) What is its average velocity?
(b) Can you calculate its average speed from these data?