Question

1- A boy starts from a point A, travels to a point B at a distance of 3 km from A returns to A. If he takes two hours to do so, his speed is (a) 3 km/h (b) zero (c)2 km/h (d) 1.5 km/h ​

Answer 1

Given info : A body starts from a point A, travels to a point B at a distance of 3 km form A returns to A.

To find : if he takes two hours to do so, his speed is ...

solution : speed of a body is the rate of change of distance covered by the body with respect to time.

 i.e., speed = total distance covered/total time taken

here total distance covered by the boy = distance between A and B + distance B and A = 3 km + 3 km = 6 km

total time taken by the boy = 2 hrs

now the speed of the boy = 6 km/2 hrs = 3 km/h

Therefore the speed of the boy is 3 km/h.

[note : here total displacement of the boy will be zero because initial position and final position of boy are same. so the average velocity of the boy will be zero.  ]

Answer 2

Answer:

(c)2 km/h

Explanation: