Question

An object moves from position +34m to the position -15m in 15 seconds. What is the total displacement? What is the total velocity?

Answer 1

1) Displacement: -49 m, in the negative direction

Explanation:

The displacement of an object is a vector, whose magnitude is given by the difference between the final point of the motion and the starting point:

$d=p_f -p_i$

In this problem, the starting point is +34 m, while the final position is -15 m; therefore, the displacement is:

$d=-15 m- (+34 m)=-49 m$

and the direction is negative, in according to the negative sign.

2) Velocity: -3.27 m/s

Explanation:

Velocity is equal to the ratio between the displacement and the time taken:

$v=\frac{d}{t}$

in this problem, we have:

d = -49 m is the displacement

t = 15 s is the time

therefore, the velocity is

$v=\frac{-49 m}{15 s}=-3.27 m/s$

and the direction is negative.