Question

A block of wood weigh 4 N in air and 3N when immersed in a liquid. Find out the upthrust acting on it.

Answer 1

Weight acts downward
and upthrust act upward.

Actual weight of body = weight in air =4N

Let the upthrust be x.

So, when the body is immersed in water, upthrust act on it.
Now, weight(4N) is downward and upthrust(x) is upward.

So, resultant weight of body in water =4-x

It is given that weight in water =3N

So equates it.

4-x=3
x=4-3=1N

So, upthrust =1N

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