Question

18. Water from a tap emerges vertically
down with an initial speed of 1.0ms-1. The
cross sectional area of tap is 10 x 10-5 m².
Assume that the pressure is constant
throughout the stream of water, and that
the flow is a steady, the cross sectional area
of the steam 0.15m below the tap is
1) 5.0 x 10-4m? 2) 1.0 x 10-5m²
3) 5.0 x 10-5m² 4) 2.0 x 10-5m²​

Answer 1

Explanation:

The equation of continuity is v1A=v2A2

where v and A represent the speed of water stream and its area of cross section, respectively. We are given that

v1=1.0ms-1

A1=10-4m2

v2= velocity of water stream at 0.15m below the tap

A2=?

For calculating v2

u=1m/s , s=1.5m, a=10m/s2 and v=?

v2-u2=2as

v2-1=2×10×0.15⇒v=2m/s

Hence, A2=

v1A1

v2

=

1×10-4

2

=5×10-5m2