buoyant force in liquid vs. air

This forum made possible through the generous support of SDN members, donors, and sponsors. Thank you.

SaintJude

Full Member
10+ Year Member
Joined
Jan 4, 2012
Messages
1,479
Reaction score
5
A cube of wood whose side are each 10 cm weight 16 N in air. When half submerged in an unknown liquid, it weights only 10 N.

Why is the buoyant force the difference between an object's weight in air and that in liquid? (So in this question, Fb=6?)

Members don't see this ad.
 
Last edited:
By weight in the water they mean the force pulling down the cube. That's its weight minus the buoyant force. In air the weight is just that - the weight.
 
Members don't see this ad :)
1.) How did you know the "weight in the water" is actually the "force pulling down the cube. " ?
 
Last edited:
What else could it be? Weight is the force that Earth exerts on the object by gravity. So if you want to be very precise, the weight should be the same in both cases. But it's customary to refer as weight to the force that pulls a body down towards the Earth.
 
Top