Between kinetic energy and potential energy, what type of energy increased in each of the...

Question:

Between kinetic energy and potential energy, what type of energy increased in each of the following examples?

1. A car accelerating from 0 mph to 60 mph.

2. A baseball thrown by a pitcher.

3. A spring compressed by 10 cm.

4. A ball rolls down a hill.

5. The temperature of a gas is increased.

6. A book picked up off the floor and put on a table.

Mechanical Energy:

The total energy needed to perform work can be categorized into two quantities: the kinetic energy, or the energy that an object has while in motion, and; the potential, or the energy an object gathers while being at rest and is constantly applied a certain force.

Answer and Explanation:

Kinetic energy is the energy in motion; potential energy is the gathered energy while being at rest.

1.

The object increases its velocity, so the kinetic energy is increased.

2.

As the ball moves, it experiences a constant downward force due to gravity. Therefore, it experiences acceleration and an increase in velocity. Consequently, kinetic energy also increases.

3.

The expression for a spring's potential energy is given by:

{eq}U = \frac{1}{2}k(\Delta x)^2 {/eq},

where x is the compression length.

From a certain length, we compressed it by 10 cm, which increases the {eq}\Delta x {/eq}, also increasing the potential energy.

4.

Similar to item 2, the ball also experiences a constant downward force from gravity, therefore experiencing a constant downward acceleration, therefore causing an increase in velocity and consequently, kinetic energy.

5.

Increasing a gas's temperature increases the energy between the molecules, causing them to move about. This motion signifies an increase in velocity, therefore it equates to kinetic energy.

6.

Gravitational potential energy can also be written as:

{eq}U = mg\Delta h {/eq}.

Here, h is the height of the object from the ground. An increase of height from the surface equates to an increase in potential energy.


Learn more about this topic:

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Kinetic Energy to Potential Energy: Relationship in Different Energy Types

from CLEP Natural Sciences: Study Guide & Test Prep

Chapter 3 / Lesson 2
314K

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