Question

A 30 N crate is submerged in water. The amount of buoyant force acting on the crate is 25 N. What will the crate do? The crate will float and accelerate upwards. The only force acting on the crate is the buoyant force, and it acts upwards on the crate. The crate will sink and accelerate downwards. The buoyant force acting upwards on the crate is smaller than the downward force of gravity on the crate. The crate will sink and accelerate downwards. The buoyant force and the gravitational force are both acting downwards on the crate, making it accelerate down. The crate will sink and accelerate downwards. The only force acting on the crate is the buoyant force, and it acts downwards on the crate.

Answer 1

Answer: The buoyant force acting upwards on the crate is smaller than the downward force of gravity on the crate. The crate will sink and accelerate downwards

Explanation:

At any moment, while the crate remains submerged in water, there are two external forces acting on the crate: the gravity force (in this case, 30 N), that aims always downward, and the buoyant force, due to the water removed by the crate while it is being submerged, which is always upwards.

As in this case the buoyant force is smaller than the weight of the crate, there is a net force pointing downward, causing the object to sink and accelerate downwards in order to be compliant with Newton's 2nd Law.