Question

A boy is running on a straight road re runs 500 m towards north in 2 mins 10 secs and then turns back and runs 200 meter in 1 min. Calculate-
i) his avg. Speed and magnitude of average velocity during 1st 2 minutes 10 secs and
ii) his average speed and magnitude if average velocity during the whole journey .​

Answer 1

Explanation:

(i)

• Total Distance travelled =500m
• Total time taken= 2min 10sec=130sec
• Avg. Speed= total dist./total time

=500/130m/sec =50/13 m/s

$= 3 \frac{11}{13} \: {ms}^{ - 1}$

[Ans.]

Avg. Velocity= total displacement/total time

=avg. speed (total distance travelled=total displacement)

=

$3 \frac{11}{13} \: {ms}^{ - 1}$

[Ans.]

(ii)

• Total distance travelled= (500+200)m=700m
• Total time= 130s+60s=190s
• Total displacement= (500-200)m=300m

Avg. speed= total dist./total time

=700/190

$= 3 \frac{13}{19} \: {ms}^{ - 1}$

[Ans.]

Avg. velocity= total displacement/total time

=300/190

$= 1 \frac{11}{19} \: {ms}^{ - 1}$

[Ans.]