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## Homework Statement

Serway Physics - P2.40

A glider of length 12.4 cm moves on an air track with constant acceleration (Fig P2.39).

A time interval of 0.628 s elapses between the moment when its front end passes a fixed

point A along the track and the moment when its back end passes this pont. Next, a time

interval of 1.39 s elapses between the moment when the back end of the glider passes the

point A and the moment when the front end of the glider passes a second point B further

down the track. After that an additional 0.431 s elapses until the back end of the glider

passes point B.

(a) Find the average speed of the glider as it passes point A.

(b) Find the acceleration of the glider.

(c) Explain how you can compute the acceleration without knowing the distance

between points A and B

## Homework Equations

## The Attempt at a Solution

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(a) For constant acceleration I know that ##v_{x,avg}=\frac {v_{xi} + v_{xf}} {2} ## (1)

Also I know that ##x_f=x_i + \frac {v_{xi} + v_{xf}} {2} t## (2)

So ##(2) => v_{x,avg} = \frac {x_f - x_i} {t} = \frac {12.4cm} {0.626s} = 19.74cm/s##

Is part (a) correct?

How do I find part (b) and (c)?