Educational worksheet on Force, Work, and Energy for Grade V, including fill-in-the-blank, multiple choice, definition, and short answer questions.

Let's solve each part of this worksheet step by step and explain the answers clearly.

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1. Fill in the blanks

a. Earth exerts a ______ force on us.
✔ Answer: *Gravitational*
Explanation: The Earth pulls objects toward its center due to gravity. This pulling force is called gravitational force.

b. The radio is a source of ______ energy.
✔ Answer: *Sound*
Explanation: A radio converts electrical energy into sound energy, which we hear as music or speech.

c. Many simple machines apply ______ force on the object.
✔ Answer: *Mechanical*
Explanation: Simple machines (like levers, pulleys, inclined planes) help us apply mechanical force to make work easier.

d. ______ is the main source of heat energy.
✔ Answer: *The Sun*
Explanation: The Sun is the primary natural source of heat energy for Earth through solar radiation.

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2. Choose the correct word

a. When you lift your books from the desk you apply (muscular / frictional) force.
✔ Answer: *Muscular*
Explanation: You use your muscles to lift the books, so it’s muscular force.

b. When we switch on a bulb, electrical energy is changed into (solar / light) energy.
✔ Answer: *Light*
Explanation: An electric bulb converts electrical energy into light energy (and some heat).

c. The greater the force, the (lowest / fastest) will be the speed.
✔ Answer: *Fastest*
Explanation: According to Newton’s second law, greater force leads to greater acceleration, which increases speed faster.

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3. Define

a. Buoyant force
✔ Answer: *Buoyant force is the upward force exerted by a fluid (liquid or gas) on an object immersed in it.*
Explanation: It's why objects float or feel lighter in water. It acts opposite to gravity.

b. Work
✔ Answer: *Work is done when a force causes an object to move in the direction of the force.*
Formula: Work = Force × Distance (in the direction of force). Unit: Joule (J).

c. Energy
✔ Answer: *Energy is the capacity or ability to do work.*
Explanation: It can exist in many forms like kinetic, potential, heat, sound, etc.

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4. Think and answer

a. What will happen if there were no gravitational force?
✔ Answer: If there were no gravitational force, objects would not stay on Earth — they would float away. Planets wouldn’t orbit the Sun, and life as we know it would not exist.

b. Can you name the energy possessed by a stone at the top of a mountain?
✔ Answer: *Potential energy*
Explanation: The stone has gravitational potential energy because of its height above the ground. It can fall and convert that energy into motion (kinetic energy).

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5. Answer in one or two sentences

*(Note: The question isn't fully visible, but based on context, here are possible responses to common follow-up questions.)*

Example Question: *Why is work done when lifting a box?*
✔ Answer: Work is done because a force is applied to the box, and it moves upward in the direction of the force.

Example Question: *How does a roller coaster use energy?*
✔ Answer: A roller coaster uses gravitational potential energy at the top of hills, which turns into kinetic energy as it descends.

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✔ Final Answers Summary:

#### 1. Fill in the blanks:
a. Gravitational
b. Sound
c. Mechanical
d. The Sun

#### 2. Choose correct word:
a. Muscular
b. Light
c. Fastest

#### 3. Definitions:
a. Buoyant force – Upward force exerted by a fluid on an object submerged in it.
b. Work – Force applied over a distance; measured in joules.
c. Energy – Ability to do work; exists in various forms.

#### 4. Think and answer:
a. Without gravity, objects would float away, planets wouldn’t orbit, and life couldn’t exist.
b. The stone has gravitational potential energy.

#### 5. One or two sentence answers (example):
- Work is done when a force moves an object in its direction.
- Potential energy is stored energy due to position or state.

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