Question

A car moves from A to B with a uniform speed u and returns to B with a uniform speed v. The average speed for this round trip is _____

Answer 1

Answer:

2uv/(u+v)

Explanation:

Let the distance between points A and B is x.

Also, let the time taken

From A to B = t1

From B to A = t2

Now, it's given that,

Uniform speed from

A to B = u

B to A = v

Therefore, we have,

=> t1 = x/u

=> t2 = x/v

Now, we know that,

Average speed = Total distance/Total time

Therefore, we hvae,

=> Avg. speed = (x+x)/(x/u+x/v)

=> Avg. speed = 2x/(ux+vx)/uv

=> Avg. speed = 2uvx/x(u+v)

=> Avg. speed = 2uv/(u+v)

Hence, the required answer is 2uv/(u+v).