Question

A child moving on a circular track of radius 40 meter complete one revolution in 5 minute
what is his average speed and average velocity in full revolution.

Answer 1

Here,

Radius = 40m

circumference= π×40^(2)

= 5026.5m

So,

distance travelled = 5026.5m

Time taken = 5min/ 300sec

Average speed = Distance/ time

= 5026.5/ 300

= 16.75m/sec

After completing one revolution the total displacement of the child is zero

Hence,

Averege velocity = Displacement/ time

= 0/300sec

= 0

Answer 2

Therefore the speed of the boy is 0.84 m/s and the velocity of the boy is 0 m/s.

Given:

The radius of the circular track = 40 m

Time taken to complete 1 revolution = 5 minutes

To Find:

The average speed and the average velocity in full revolution.

Solution:

The given question can be solved as shown below.

Given that,

The radius of the circular track = 40 m

Time taken to complete 1 revolution = 5 minutes = 5 × 60 seconds = 300 seconds

Distance traveled by the boy = circumference of the circle = 2πr = 80π

Displacement traveled by the boy = Shortest distance between the initial point and final point

For full revolution, the initial point and final point coincide, So displacement = 0

⇒ Average speed = ( Total distance )/( Total time ) = 80π/300 = 4π/15 m/s = 0.84 m/s

⇒ Average velocity = ( Total displacement )/( Total time ) =0/300 = 0 m/s

Therefore the speed of the boy is 0.84 m/s and the velocity of the boy is 0 m/s.

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