Question

An empty plastic bottle floats, while a plastic bottle filled with sand sinks in water because

• A. density of empty plastic bottle is more than density of water
• B. density of empty plastic bottle is more than density of plastic bottle filled with sand
• C. density of empty plastic bottle is less than density of water
• D. density of empty plastic bottle is less than density of plastic bottle filled with sand

Answer 1

The correct option is C

density of empty plastic bottle is less than density of water

The gravitational pull on the empty plastic bottle is equal to the upthrust exerted on it by the water. In other words, its density is less than density of water, therefore, it floats. On the other hand, a plastic bottle filled with sand sinks as the gravitational pull on it(weight) is more than the upthrust of water.