Question

A boy is running on a straight road. He runs 500m towards North in 2 minutes 10 seconds
and then turns back and runs 200m in 1 minute. Calculate: (a) his average speed and
magnitude of average velocity during first 2minutes 10 seconds. (b) his average speed
and magnitude of average velocity during the whole journey.

Answer 1

Answer:

Explanation:

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