Science worksheet on work and energy with fill-in-the-blank questions.

Problem: Fill in the blanks related to work and energy based on the provided worksheet.

#### What is work?
1. In science, work is done when a force changes the motion of an object.
- Explanation: Work is defined as the transfer of energy that occurs when a force causes an object to move in the direction of the force.

2. Picking up a book is work because a force is used and the book moves.
- Explanation: When you pick up a book, you apply a force (lifting force) that causes the book to move upward from its initial position.

3. Dropping a book is work because gravity changes the motion of the book.
- Explanation: Gravity exerts a force on the book, causing it to accelerate downward and change its motion.

4. Work is not done on an object when you push it and it does not move.
- Explanation: For work to be done, there must be displacement in the direction of the applied force. If the object does not move, no work is done.

5. Picking up a boulder is more work than picking up a pebble.
- Explanation: The amount of work done depends on the force applied and the distance over which the force is applied. Since a boulder is much heavier than a pebble, more force is required to lift it, resulting in more work being done.

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#### What is energy?
6. People need energy to do work.
- Explanation: Energy is the capacity to do work. Without energy, no work can be performed.

7. The ability to do work is a way to describe energy.
- Explanation: Energy is defined as the ability to perform work. This means that anything that has the capacity to cause motion or change is said to have energy.

8. Energy makes it possible for changes in motion to take place.
- Explanation: Energy is required to change the state of motion of an object. For example, applying energy (force) can make a stationary object move or stop a moving object.

9. The two main forms of energy are kinetic energy and potential energy.
- Explanation: Kinetic energy is the energy of motion, while potential energy is stored energy due to an object's position or configuration.

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Final Answers:

1. Work
2. moves
3. gravity
4. move
5. more
6. energy
7. work, energy
8. motion
9. kinetic energy, potential energy

Completed Worksheet:

```
What is work?
1. In science, work is done when a force changes the motion of an object.
2. Picking up a book is work because a force is used and the book moves.
3. Dropping a book is work because gravity changes the motion of the book.
4. Work is not done on an object when you push it and it does not move.
5. Picking up a boulder is more work than picking up a pebble.

What is energy?
6. People need energy to do work.
7. The ability to do work is a way to describe energy.
8. Energy makes it possible for changes in motion to take place.
9. The two main forms of energy are kinetic energy and potential energy.
```

Final Answer:
\boxed{
\text{1. Work, 2. moves, 3. gravity, 4. move, 5. more, 6. energy, 7. work, energy, 8. motion, 9. kinetic energy, potential energy}
}