Why can a steel ship float although steel is denser than water?
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A ship contains large air-filled spaces.
Its total mass spread over its volume gives an average density below water.
Practice PMS questions with answers and explanations.
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A ship contains large air-filled spaces.
Its total mass spread over its volume gives an average density below water.
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Density compares mass with the space occupied.
It is calculated as mass divided by volume.
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Ice has an open crystal structure that occupies more volume.
Its lower density causes it to float on water.
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Freezing expands water into a less dense solid structure.
The resulting ice is buoyant in liquid water.
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A raised object has energy because of its position in a gravitational field.
This energy can convert to kinetic energy as it falls.
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Kinetic energy is the energy of motion.
It depends on the object's mass and speed.
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Inertia causes an object to remain at rest or in uniform motion unless acted on.
Greater mass generally means greater inertia.
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The fan's motor converts electrical energy into rotation.
Some energy is also lost as heat and sound.
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Their bodies tend to continue moving forward when the bus stops.
This is an example of inertia of motion.
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Chemical reactions inside a battery create an electric potential.
The stored chemical energy is converted into electrical energy.
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Newton's third law describes paired interaction forces.
Each force is matched by an equal force in the opposite direction.
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Solar cells use the photovoltaic effect.
They convert light directly into electrical energy.