Question

If an object starts at rest and moves 60 meters north along a straight line for 2 seconds, what is its average velocity?

Question 5 options:

a) 120 m/s
b) 30 m/s
c) 60 m/s
d) 30 m/s, north

Answer 1

answer is d 30 m/s, North

Given: Distance d = 60 m;     Time  t = 2 seconds

Required: Average Velocity  Vave. Vi + Vf/2

Formula: d = 1/2 at²   derive acceleration a = ?   and       a = Vf - Vi/t

               a = 2d/t²
             
               a = 1/2(60 m)/( 2 s)²

               a = 30 m/s²

Solve for final Velocity   Vf = ?

               a = Vf -Vi/t

               Vf = at     Since Initial Velocity is zero

               Vf = (30 m/s²)(2 s)

               Vf = 60 S


For average velocity Vave. = Vi + Vf/2

                                 Vave. 0 + 60 m/s/2

                                 Vave = 30 m/s  North.