Question

Ann jogs from one end A to the other end B of a straight 300 m road in 2 minutes 50 seconds. She then turns around and jogs 100 m back to point C in another 1 minute. What are Ann's average speeds and velocities in jogging from A to B and from A to C?

• A. A to B-
  Speed: 1.76 m/s
  Velocity: 1.76 m/s
  B to C-
  Speed: 1.74 m/s
  Velocity: 0.869 m/s
• B. A to B-
  Speed: 0.869m/s
  Velocity: 1.76m/s
  B to C-
  Speed: 1.74m/s
  Velocity: 0
• C. A to B-
  Speed: 1.76m/s
  Velocity: 0.869m/s
  B to C-
  Speed: 0
  Velocity: 1.74m/s
• D. A to B-
  Speed: 0.869m/s
  Velocity: 1.76m/s
  B to C-
  Speed: 1.74m/s
  Velocity: 1.74 m/s

Answer 1

The correct option is A A to B-

Speed: 1.76 m/s
Velocity: 1.76 m/s
B to C-
Speed: 1.74 m/s
Velocity: 0.869 m/s
From A to B:
Time taken $t_1=2min50s=2\times 60+50=170s$
Distance travelled is equal to the displacement, $s_1=300m$
Average speed is equal to the average velocity:
$v_1=\frac{300}{170}=1.76m/s$.

From A to C:
Time taken, $t_2=170+60=230s$
Distance travelled, $d_2=300+100=400m$
Average speed, $v_{2,s}=\frac{400}{230}=1.74m/s$

Displacement, $s_2=AC=300-100=200m$
Average velocity, $v_{2,v}=\frac{200}{230}=0.869m/s$