Q553
What is the principle of a ''Life Jacket"?
A.
It provides oxygen to a drowning person
B.
It increases the volume of the person to keep him afloat
AnswerC.
It decreases the volume of the person to keep him afloat
D.
The person can sit on it like a raft
Answer: Option B
Solution
Answer: Option B
Solution:
The upward-pushing force that keeps things afloat is called buoyancy. For an object to float it must be able to equal its own weight by displacing enough water. A life jacket is mainly filled with gas which has a very low mass. As such when worn by a person, it acts to significantly increase their volume for only a very small increase in their mass. This means that they have a lower density than normal which increases their buoyancy and helps them to float.