Question

20. A man travels along a straight
road for the first half length with
a velocity u and the second half
length with a velocity v. Then, the
mean velocity is given by
2uv
(a)
(b)
U + V
(d) zero
utv
Sh-la
34/3
2
(c) uy
tont​

Answer 1

Let the total distance be d.

Time taken for the first half half distance is t

1

=

2v

1

d

Time taken for the second half of the distance is t

2

=

2v

2

d

Mean velocity =

total time

total distance

v

mean

=

2v

2

d

+

2v

1

d

d

v

mean

=

v

1

+v

2

2v

1

v

2

⇒

v

mean

2

=

v

1

1

+

v

2

1

Given, v

mean

=v

⇒

v

2

=

v

1

1

+

v

2

1