Will pseudo force effect buoyant force in a liquid? Imagine a body in a tub which is in a lift. When the lift is stationary, the body is floating. If the lift accelerates upwards with a constant acceleration, what will happen to the buoyancy? Will its value change or not?
I do not think it shouldn't. But my friend says it will. But why?
 A: A lift is a somewhat complicated example because a lift can be stationary, moving at constant speed or accelerating (or decelerating) and this affects the forces felt by the objects in it. Perhaps a better example would be to ask if the system changes as the force of gravity is changed, e.g. by raising the system to different heights.
Having said this, it doesn't make any difference. Archimedes' principle tells us that the floating object displaces a volume of water $V$ where the weight of this water $V\rho_w g$ equals the weight of the object $mg$ so we can write an expression for the volume of water displaced:
$$ V = \frac{m}{\rho_w} $$
Note that the acceleration due to gravity, $g$, cancels out so the bouyancy is not affected by changes in the gravity (or acceleration in a lift).
There may be small effects that become important at very high accelerations. For example at high accelerations the floating object my be compressed by the pressure exerted by the water and this would reduce its bouyancy. This is unlikely to be significant in a lift.
