Force Work and Energy Class 5 Questions and Answers

Short answer questions.

1. Why are machines used? 

Ans: A machine is a tool that makes our work easier

• . It helps us to overcome a larger force (required to move a load) by applying a lesser force (called effort).

2. What is a lever? Name the three types of levers. 

Ans: A lever is a simple machine consisting of a rigid rod which is capable of turning around a pivot called a fulcrum.

 It has three parts, namely,

• effort
• load
• fulcrum.

Based on the position of the fulcrum(pivot), load, and effort, levers are of the following three kinds:

•  First class lever
• Second class lever
• Third class lever

3. Define wedge. 

Ans.

•  A wedge is a simple machine that has a long triangular shape with one broad or blunt end, and one sharp end. 
• The sharp end is used to cut or slice objects.
•  A wedge may also be formed when two inclined planes are joined together.

Examples: The head of an axe and the blade of a knife are examples of a wedge. 

4. Name the different types of forces.

Ans:

• Frictional Force
• Tension Force
• Normal Force
• Air Resistance Force
• Gravitational Force
• Electrical Force

5. Why is geothermal energy referred to as a renewable source of energy? From where does most of the heat energy come?

Ans: Geothermal energy is a type of renewable energy taken from the Earth’s core which will never exhaust , that’s why it is renewable.

 It comes from heat generated during the original formation of the planet and the radioactive decay of materials. This thermal energy is stored in rocks and fluids in the center of the earth.

6. Name four different forms of energy. 

Ans: Energy exists in many different forms. Examples of these are: light energy, heat energy, mechanical energy, gravitational energy, electrical energy, sound energy, and so on.

Also Check – Force Work And Energy – Class 5 – Notes

7. What is an inclined plane? How is it useful for us? 

Ans: An inclined plane is a tilted surface or a slope 

• An inclined plane is  used to move a heavy load with less effort. 

8. Does a screw join two pieces of wood better than a nail? How? 

Ans: A screw is better than nails as it holds things better than a nail . This is due to the presence of threading in screws that grips the surrounding material tightly. Also screws are easier to control than nails and can be removed easily.

9.What is the law of conservation of energy?

Ans: The law of conservation of energy states that energy can neither be created nor destroyed – only converted from one form of energy to another. This means that a system always has the same amount of energy, unless it’s added from the outside. 

10. How is wind energy more environment friendly than heat energy?

Ans: Using wind to produce energy has fewer effects on the environment than many other energy sources like heat. Wind turbines do not release emissions that can pollute the air or water (with rare exceptions), and they do not require water for cooling as needed to produce heat energy

11. With the help of suitable examples, discuss when work is done, and when not.

Ans:

Examples of work done:

•  pulling or pushing a cart through some distance 
• Carrying a load up a staircase pushing and moving a box up a ramp
•  Running or jogging 
•  Playing outdoor sports such as football and badminton 
•  Swimming 

Examples of work not being done 

•  Reading a book or studying for an examination 
•  Holding a heavy load, but not moving
•  Pushing a heavy box or wall that does not move 

12. You have to load your suitcase on to a truck. You are not able to lift the suitcase. Which simple machine can help you do this? Why?

Ans: We should use an inclined plane as an inclined plane is  used to move a heavy load with less effort. 

13. A single fixed pulley does not reduce the effort required to lift a load. How does it make our work easier? 

Ans : Such a pulley makes our work easier by simply changing the direction of the force, i.e. a load is lifted up using a downward effort. It is easier to lift a load up by pulling it down rather than by pulling it up directly.

Also Check – Force Work And Energy – Worksheet – Solved

Long answer questions.

1. What is a simple machine? Name some simple machines and draw diagrams too.

Ans: A simple machine uses a single applied force to get the work done.

•  A “simple” machine is one where both the input energy and the output energy are mechanical in nature .
•  A simple machine has very few parts. 
• A wheelbarrow is an example of a simple machine

Types of Simple Machines

There are mainly 6 types of simple machines.

•  A lever
• pulley
• wheel and axle
• wedge
• screw
• and an inclined plane are some simple machines.

3. What is the difference between work and energy?

 Ans :  Difference Between work And energy 

Work	Energy
Work is the result of energy transferred to an object due to some force.	Energy is defined as the property of matter through which it does work.
Can be either positive or negative.	It is always positive, but the change in energy may be negative.
If the applied force is in the same direction of the displacement than work is positive It the applied force is in the opposite direction of the displacement that work is negative	The is no direction component here as it is a scalar quantity

 

4. Differentiate between renewable and non-renewable energy. 

 

Renewable Resources	Non-renewable Resources
Renewable resources cannot be depleted over time	Non-renewable resources deplete over time
Renewable resources include sunlight, water, wind and also geothermal sources such as hot springs .	Non-renewable energy includes fossil fuels such as coal and petroleum.
Most renewable resources cause less pollution	Non-renewable energy cause more pollution

5. Write a note on wind energy and solar energy. 

Ans: 

WIND ENERGY

• The energy present in moving air or wind is called wind energy.
• Wind is used to produce electricity using wind turbines or wind energy conversion systems.

SOLAR ENERGY

• The energy that we get from sunlight is called solar energy.
• It can be used to carry out many functions on the Earth.
• Solar energy is abundant on Earth and is also non-polluting.
• When electricity is obtained from burning fuels, smoke and other polluting gases are formed. But when we use solar energy to get electricity, there is no pollution. 

Examples:  

• Solar panels convert solar energy into electrical energy, which is used to run machines.
•  Solar cookers use sunlight to cook food.