Question

☆☆Pls helppp☆☆ Class 9 question

A boy is running on a straight road. He runs 500m towards north in 2.10mins.
And then turns back and runs 200m in 1min. Calculate
a. His average speed and magnitude of average velocity during the first 2.10min
b. His average speed and magnitude of average velocity during the whole journey.

☆☆Pls write it down ... Will mark brainliest asap:) literally asap☆☆​

Answer 1

Let the boy start from a point A and B point is 500 m away from it .

And a C point which is 200 m away from point B .

Now

Time taken to reach at point B.

T= 130s

Distance = 500m

avg speed = 500/ 130

= 3.7m/s

displacement = 500m

v.avg = 500 / 130

= 50 / 13

= 3.7 m/s

Total joutney's avg speed

= (500/ 130 + 200 / 60 ) / 2

= ( 3.7 + 3.3 ) / 2

= 7 / 2

= 3. 5 m/s

as we know the AC = 300m

And time taken from reaching A to C is

= 130 - 60 sec

= 70 sec

Total avg velocity

= 300 / 70

= 4.2 m/s