JIPMER2017PhysicsMechanical Properties of Fluids
A wide hose pipe is held horizontally by a fireman. It delivers water through a nozle at one lirte per second. On increasing the pressure, this increass to two litres per second. The fireman has now to
Options
- Apush forward twice as hard
- Bpush forward four times as hard
- Cpush backward four times as hard
- Dpush backward twice as hard.
Correct answer
B. push forward four times as hard
Step-by-step solution
Rate of change of mass, d m d t =a v F= v d m d t =(a v ) v=a v^2 Volume of liquid flowing per second =a v This is proportional to velocity. By doubling the volume of liquid flow per second, the force becomes four times. When liquid flows forward, the hose pipe tends to come backward. So, to keep it intact, it should be pushed forward. Thus, the hose pipe should be pushed forward four times.