You haven't said "more or less" than what.
He weighs more than a beach ball and less than a manatee.
Everybody weighs less in water than they do out of it. But every person weighs
more than some other people and less that some other other people, whether
any of them are in or out of the water.
It will weigh more because the total weight would be the sum of the person's weight and the weight of the water in the barrel.
Objects under water seem to weigh less but they have the same mass as they would out of water.
A human will weigh the same in water as they do outside of water. However, when submerged in water, the body will experience buoyant force that counteracts some of the weight, making the person feel lighter.
You may weigh less after a shower because the water on your body adds weight, and some of it is lost as the water evaporates.
yes
because there's less water in it.
no
No. Oil is less dense than water, so 1 liter of oil will weigh less than 1 liter of water.
You may weigh less after a shower because the water on your body evaporates, removing some weight temporarily.
the person will weigh less because of the buoyant force acting upwards, depending upon the volume of water displaced by the person.
An average person would weigh 6 times less than their actual weight.
On Mars you weigh 30% of what you do on Earth. For example, if you weigh 122lbs on Earth, you would only weigh 46lbs on Mars.