A1 cm^3 block with a density of 0.92 g/cm^3 is floating in a container of water (d =1g/ cm^3). you may ignore any air pressure throughout this problem. what buoyant force is necessary to keep the block from sinking?

980 dyne

Explanation:

Volume = 1 cm^3, d = 0.92 g / cm^3, D = 1 g/cm^3

In the equilibrium condition, the buoyant force is equal to the weight of the block.

Buoyant force = Volume of block x density of water x g

Buoyant force = 1 x 1 x 980 = 980 dyne

the one with the highest speed

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.