Question

Question 13 8 pts An object completely submerged in an incompressible fluid is at rest. Which of the following are true? (Select all that apply.) If the object is pushed slightly downwards it will keep moving downwards with constant velocity If the object is pushed slightly upwards it will slow down until it comes to rest If the object is pushed slightly downwards it will slow down until it comes to rest If the object is pushed slightly upwards it will keep moving upwards with constant velocity The mean density of the object is the same as that of the fluid

Answer 1

1) if object is completely submerged in fluid then it means density of object is same as density of fluid . So that gravitational force on object is equal to the buyoncy force.

So Fg = Fb

So in that case if we push it slightly upward or downward then it will acquire a constant terminal velocity.

So option a) d) e)

2) momentum of system is always conserved in all collision and kinetic energy is conserved in elastic collision

So ∆p =∆K =0

And because momentum is conserved means

Impulse value is close to zero

So,

Fext. << Fint

And

tsys << tint

Option a) c) d) e)