AK SCI Review - Physical Sci 3

What is the formula for calculating kinetic energy?

Answer explanation

The correct formula for calculating kinetic energy (KE) is \( KE = \frac{1}{2}mv^2 \). This formula shows that kinetic energy is proportional to the mass (m) of an object and the square of its velocity (v).

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AK.SCI.6-8.MS-PS3-1

Which of the following best describes potential energy?

• Energy due to motion

• Energy stored due to position

• Energy transferred by heat

• Energy used in chemical reactions

Answer explanation

Potential energy is best described as energy stored due to position. It refers to the energy an object possesses because of its location or arrangement, unlike kinetic energy, which is due to motion.

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AK.SCI.6-8.MS-PS3-2

If the speed of an object doubles, how does its kinetic energy change?

• It remains the same

• It doubles

• It triples

• It quadruples

Answer explanation

Kinetic energy (KE) is given by the formula KE = 1/2 mv². If the speed (v) doubles, the new KE becomes 1/2 m(2v)² = 2mv², which is 4 times the original KE. Thus, it quadruples.

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AK.SCI.6-8.MS-PS3-1

Which of the following scenarios involves the transfer of thermal energy?

• A book resting on a table

• Ice melting in a glass of water

• A car parked in a garage

• A ball rolling on the ground

Answer explanation

Ice melting in a glass of water involves the transfer of thermal energy as heat from the water warms the ice, causing it to change from solid to liquid.

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AK.SCI.6-8.MS-PS3-3

A student constructs a simple pendulum. What type of energy transformation occurs as the pendulum swings from its highest point to its lowest point?

• Kinetic to potential

• Potential to kinetic

• Thermal to kinetic

• Chemical to potential

Answer explanation

As the pendulum swings down, it loses height, converting potential energy into kinetic energy. At the highest point, potential energy is maximum, and at the lowest point, kinetic energy is maximum, confirming the transformation from potential to kinetic.

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AK.SCI.6-8.MS-PS3-2

Design a simple experiment to test how the mass of an object affects its kinetic energy when dropped from a certain height.

• Use a single ball and drop it from different heights, measure the speed upon impact

• Drop balls of the same size but different masses from the same height and measure their speed upon impact

• Drop objects of the same mass but different shapes from different heights

• Measure the temperature change of the objects

Answer explanation

The correct choice is to drop objects of different masses from the same height and measure their speed upon impact. This directly tests how mass affects kinetic energy, as kinetic energy depends on both mass and velocity.

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AK.SCI.6-8.MS-PS3-1

Which of the following best describes the relationship between temperature and kinetic energy of particles in a substance?

• As temperature increases, kinetic energy decreases

• As temperature decreases, kinetic energy increases

• As temperature increases, kinetic energy increases

• Temperature and kinetic energy are unrelated

Answer explanation

As temperature increases, the average kinetic energy of particles in a substance also increases. This is because temperature is a measure of the energy of motion of particles, leading to greater movement at higher temperatures.

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AK.SCI.6-8.MS-PS3-4

A student claims that when a ball is thrown upwards, its kinetic energy is transferred to potential energy. Construct an argument to support this claim.

• The ball's speed increases as it rises

• The ball's speed decreases as it rises, converting kinetic energy to potential energy

• The ball's mass changes as it rises

• The ball's temperature increases as it rises

Answer explanation

As the ball rises, its speed decreases due to gravity. This decrease in kinetic energy is converted into potential energy, supporting the student's claim about the energy transformation during the ball's ascent.

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AK.SCI.6-8.MS-PS3-5

Which device is designed to minimize thermal energy transfer?

• A refrigerator

• A thermos

• A heater

• A fan

Answer explanation

A thermos is specifically designed to minimize thermal energy transfer, keeping hot liquids hot and cold liquids cold. In contrast, a refrigerator and heater transfer energy, while a fan circulates air without insulation.

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AK.SCI.6-8.MS-PS3-3

How does the mass of an object affect its potential energy when lifted to a certain height?

• Potential energy decreases with mass

• Potential energy increases with mass

• Potential energy is independent of mass

• Potential energy becomes zero with mass

Answer explanation

Potential energy (PE) is calculated using the formula PE = mgh, where m is mass, g is gravitational acceleration, and h is height. As mass increases, potential energy increases proportionally when lifted to the same height.

Tags

AK.SCI.6-8.MS-PS3-2