Simple Machine 9

 Simple Machine

🛠️ Technical Terms for Simple Machines​

1. Simple Machine: A device that uses a single force to perform work by changing the magnitude or direction of the force. Examples include levers, pulleys, inclined planes, etc.

2. Mechanical Advantage (MA): The ratio of the output force to the input force. It tells how much a machine multiplies force.

   • Formula: $\text{MA} = \frac{\text{Output Force}}{\text{Input Force}}$

3. Velocity Ratio (VR): The ratio of the distance moved by the effort to the distance moved by the load. It gives an idea of how the machine changes the movement speed.

   • Formula: $\text{VR} = \frac{\text{Effort Distance}}{\text{Load Distance}}$

4. Efficiency: The percentage of input energy that is converted into useful output energy in a machine.

   • Formula: $\text{Efficiency} = \frac{\text{Mechanical Advantage}}{\text{Velocity Ratio}} \times 100$

5. Load: The object or force that is being moved or lifted by the machine.

6. Effort: The force applied to the machine to move the load.

7. Fulcrum: The pivot point around which a lever rotates.

8. Lever: A simple machine consisting of a rigid bar that pivots on a fulcrum to lift or move loads. It is classified into three types:

   • First Class Lever: Fulcrum between effort and load (e.g., see-saw).
   • Second Class Lever: Load between fulcrum and effort (e.g., wheelbarrow).
   • Third Class Lever: Effort between fulcrum and load (e.g., tongs).

9. Pulley: A simple machine consisting of a wheel with a groove in which a rope can run. It changes the direction of the force and can also be used to lift heavy objects.

   • Fixed Pulley: The pulley is fixed at a point and only changes the direction of the effort.
   • Movable Pulley: The pulley moves with the load and reduces the amount of effort needed.

10. Inclined Plane: A sloped surface that allows a heavy object to be raised with less effort than lifting it vertically.

11. Wedge: A simple machine made of two inclined planes joined together, used to split or cut objects (e.g., an axe).

12. Screw: A simple machine that converts rotational motion into linear motion. It is essentially an inclined plane wrapped around a cylinder.

13. Work: The transfer of energy when a force is applied to an object and it moves. Work is calculated as $\text{Work} = \text{Force} \times \text{Distance}$

14. Mechanical Work: Work done by a machine when it applies force to move a load.

15. Power: The rate at which work is done. It is measured in watts (W).

• Formula: $$Power=Work DoneTime Taken\text{Power} = \frac{\text{Work Done}}{\text{Time Taken}}

​   ✅ ✅ ✅ Summary of Formulas

Type of Machine	Formula
Lever	Effort × Effort Arm = Load × Load Arm
Pulley	MA = Number of Supporting Ropes
Inclined Plane	MA = Length ÷ Height
Wheel and Axle	MA = Radius of Wheel ÷ Radius of Axle
Screw	MA = Circumference ÷ Pitch
Wedge	MA = Length ÷ Width
Efficiency	(Output Work ÷ Input Work) × 100

Simple Machines

Simple machines are basic mechanical devices that help make work easier by multiplying or changing the direction of force. They reduce the effort needed to perform a task.

Types of Simple Machines

There are six main types of simple machines:

1. Lever

• A rigid bar that rotates around a fixed point called the fulcrum.
• Used to lift or move loads with less effort.
• Formula:

$$\text{Effort} \times \text{Effort arm} = \text{Load} \times \text{Load arm}$$

• Types of Levers:
  • First Class Lever: Fulcrum is between the load and effort (e.g., see-saw, scissors).
  • Second Class Lever: Load is between the fulcrum and effort (e.g., wheelbarrow, bottle opener).
  • Third Class Lever: Effort is between the fulcrum and load (e.g., tongs, fishing rod).

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2. Pulley

• A wheel with a rope or chain that helps lift heavy objects by changing the direction of force.
• Types of Pulleys:
  • Fixed Pulley: Changes the direction of force (e.g., flagpole).
  • Movable Pulley: Reduces effort (e.g., construction cranes).
  • Block and Tackle: Combination of fixed and movable pulleys for greater mechanical advantage.

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3. Inclined Plane

• A flat surface set at an angle to help lift objects using less effort.
• Example: Ramp, staircase.
• Formula:

$$\text{Mechanical Advantage} = \frac{\text{Length of the inclined plane}}{\text{Height of the inclined plane}}$$

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4. Wheel and Axle

• A wheel attached to a central rod (axle) that helps rotate objects with less effort.
• Example: Steering wheel, door knob.
• Formula:

$$\text{Mechanical Advantage} = \frac{\text{Radius of Wheel}}{\text{Radius of Axle}}$$

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5. Screw

• An inclined plane wrapped around a cylinder that converts rotational force into linear force.
• Example: Screw, bottle cap.
• Formula:

$$\text{Mechanical Advantage} = \frac{\text{Circumference of screw}}{\text{Pitch of screw}}$$

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6. Wedge

• A double-inclined plane used to split or lift objects by applying force.
• Example: Knife, axe.
• Formula:

$$\text{Mechanical Advantage} = \frac{\text{Length of wedge}}{\text{Width of wedge}}$$

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Mechanical Advantage (MA)

It measures how much a machine multiplies the applied effort:

$$\text{MA} = \frac{\text{Load}}{\text{Effort}}$$

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Efficiency

Efficiency measures how effectively a machine converts input work into output work:

$$\text{Efficiency} = \frac{\text{Output Work}}{\text{Input Work}} \times 100$$

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Work and Energy in Simple Machines

• Work = Force × Distance
• Machines do not create energy; they help to use energy more effectively.

🔥 Example Summary

Machine	Example	Formula	MA
Lever	See-saw	Effort × Effort Arm = Load × Load Arm	Depends on lever type
Pulley	Crane	MA = Number of ropes	2 (movable)
Inclined Plane	Ramp	MA = Length ÷ Height	5
Wheel & Axle	Steering Wheel	MA = Radius of Wheel ÷ Radius of Axle	6
Screw	Bolt	MA = Circumference ÷ Pitch	8
Wedge	Axe	MA = Length ÷ Width	4

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✅ Key Points to Remember:

✔️ Simple machines make work easier by multiplying force or changing its direction.
✔️ Mechanical advantage helps determine how much effort is reduced.
✔️ Efficiency is never 100% due to friction.

🛠️ Technical Terms for Simple Machines

Term	Definition
Simple Machine	A device that changes the magnitude or direction of a force to make work easier.
Effort	The force applied to a machine to perform work.
Load	The object or resistance that needs to be moved or lifted by a machine.
Fulcrum	The fixed point around which a lever rotates.
Mechanical Advantage (MA)	The ratio of the load to the effort applied in a machine.
Velocity Ratio (VR)	The ratio of the distance moved by the effort to the distance moved by the load.
Efficiency	The ratio of useful output work to the input work, expressed as a percentage.
Effort Arm	The distance between the effort and the fulcrum in a lever.
Load Arm	The distance between the load and the fulcrum in a lever.
Inclined Plane	A flat surface set at an angle to reduce the effort needed to lift an object.
Wedge	A double-inclined plane used to split or lift objects.
Screw	An inclined plane wrapped around a cylinder, used to hold objects together or lift them.
Pulley	A wheel with a rope or chain that helps lift objects or change the direction of force.
Fixed Pulley	A pulley attached to a stationary object; changes the direction of force but not the effort.
Movable Pulley	A pulley that moves with the load, reducing the effort needed to lift it.
Block and Tackle	A system of fixed and movable pulleys used together to increase mechanical advantage.
Wheel and Axle	A circular object (wheel) connected to a rod (axle) that multiplies force or speed.
Input Force	The force applied to a machine.
Output Force	The force exerted by a machine on the load.
Work Done	The product of force and the distance over which the force acts. Formula: $W = F \times d$
Friction	The resistance between two surfaces that reduces efficiency in a machine.
Ideal Machine	A machine with 100% efficiency (no friction or energy loss).
Actual Machine	A machine that loses some energy due to friction and other factors.
Pitch	The distance between two threads in a screw.
Circumference	The distance around a circle (used in screws and wheels). Formula: $C = 2 \pi r$
First Class Lever	A lever where the fulcrum is between the effort and the load (e.g., see-saw).
Second Class Lever	A lever where the load is between the fulcrum and the effort (e.g., wheelbarrow).
Third Class Lever	A lever where the effort is between the fulcrum and the load (e.g., tongs).
Load Distance	The distance the load moves when the machine is used.
Effort Distance	The distance the effort moves when the machine is used.
Lever Arm	The length of the lever from the fulcrum to the point where the force is applied.
Trade-off	The relationship between force and distance in simple machines; increasing one decreases the other.
Compound Machine	A machine that combines two or more simple machines (e.g., scissors = lever + wedge).
Input Work	The work done on a machine.
Output Work	The useful work done by a machine.
Direction of Force	The path along which a force is applied to an object.
Mechanical System	A system that consists of several connected machines working together.

🛠️ 1. Simple Machine

A simple machine is a basic mechanical device that helps make work easier by:

✅ Increasing or decreasing the force needed.

✅ Changing the direction of the force.

✅ Increasing the distance or speed of movement.

✅ Examples:

• Lever
• Pulley
• Inclined Plane
• Wheel and Axle
• Wedge
• Screw

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🏋️‍♂️ 2. Effort

The effort is the force applied to a machine to perform work.

• Measured in Newtons (N).
• The machine reduces the effort needed by multiplying the applied force.

✅ Example:

• When you push down on a lever, the force you apply is the effort.

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🎯 3. Load

The load is the object or resistance that needs to be moved or lifted.

• Also measured in Newtons (N).

✅ Example:

• Lifting a stone with a lever — the stone is the load.

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🔄 4. Fulcrum

The fulcrum is the fixed point around which a lever rotates.

• The position of the fulcrum determines the type of lever and its mechanical advantage.

✅ Example:

• In a see-saw, the central point where the board balances is the fulcrum.

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🚀 5. Mechanical Advantage (MA)

The Mechanical Advantage is the ratio of the output force (load) to the input force (effort).

$$\text{MA} = \frac{\text{Load}}{\text{Effort}}$$

✅ Example:

• If you use a lever to lift a 20 N load with 5 N of effort:

$$\text{MA} = \frac{20}{5} = 4$$

👉 This means the machine multiplies the effort 4 times!

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⚡ 6. Velocity Ratio (VR)

The Velocity Ratio is the ratio of the distance moved by the effort to the distance moved by the load.

$$\text{VR} = \frac{\text{Distance moved by effort}}{\text{Distance moved by load}}$$

✅ Example:

• If the effort moves 2 m while the load moves 0.5 m:

$$\text{VR} = \frac{2}{0.5} = 4$$

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🌟 7. Efficiency

Efficiency measures how effectively a machine converts input work into useful output work.

$$\text{Efficiency} = \frac{\text{Output Work}}{\text{Input Work}} \times 100$$

✅ Example:

• If input work = 100 J and output work = 80 J:

$$\text{Efficiency} = \frac{80}{100} \times 100 = 80\%$$

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📏 8. Effort Arm

The Effort Arm is the distance between the effort and the fulcrum in a lever.

• A longer effort arm reduces the effort needed.

✅ Example:

• In a crowbar, the longer the handle (effort arm), the less effort you need to lift an object.

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📏 9. Load Arm

The Load Arm is the distance between the load and the fulcrum in a lever.

• A shorter load arm increases mechanical advantage.

✅ Example:

• In a seesaw, if the load is closer to the fulcrum, less effort is needed to lift it.

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⛰️ 10. Inclined Plane

An inclined plane is a flat surface set at an angle.

• Reduces the effort needed by increasing the distance over which the effort is applied.

✅ Formula:

$$\text{MA} = \frac{\text{Length of Plane}}{\text{Height of Plane}}$$

✅ Example:

• Pushing a box up a ramp instead of lifting it directly.

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⚙️ 11. Wheel and Axle

A wheel and axle is a circular object (wheel) connected to a rod (axle).

• Increases force or distance depending on which part you apply the effort.

✅ Formula:

$$\text{MA} = \frac{\text{Radius of Wheel}}{\text{Radius of Axle}}$$

✅ Example:

• In a steering wheel, turning the large wheel makes it easier to turn the smaller axle.

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🪢 12. Pulley

A pulley is a wheel with a rope or chain wrapped around it.

✅ Types of Pulleys:

Type	Description	Example	MA
Fixed Pulley	Changes direction of force only	Flagpole	1
Movable Pulley	Reduces effort	Construction crane	2
Block and Tackle	Combines fixed and movable pulleys	Sailboat rigging	Depends on number of pulleys

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🔪 13. Wedge

A wedge is a double inclined plane used to split or cut objects.

✅ Formula:

$$\text{MA} = \frac{\text{Length of Wedge}}{\text{Width of Wedge}}$$

✅ Example:

• Knife, axe, chisel.

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🔩 14. Screw

A screw is an inclined plane wrapped around a cylinder.

• Converts rotational motion into linear motion.

✅ Formula:

$$\text{MA} = \frac{\text{Circumference of Screw}}{\text{Pitch}}$$

• Pitch = Distance between two adjacent threads.

✅ Example:

• A bolt or drill bit.

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🚥 15. Trade-off

There’s always a trade-off between force and distance in simple machines.

👉 Increasing force ➡️ Decreases distance

👉 Increasing distance ➡️ Decreases force

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🏆 16. Compound Machine

A compound machine combines two or more simple machines to perform complex work.

✅ Example:

• Scissors (lever + wedge)
• Bicycle (wheel and axle + lever + pulley)

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🔄 17. Work Done

Work is done when a force causes an object to move in the direction of the force.

$$W = F \times d$$

where:

• W = Work (Joules)
• F = Force (Newtons)
• d = Distance (meters)

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⚠️ 18. Friction

Friction is the force that opposes motion between two surfaces in contact.

• Reduces the efficiency of machines.
• Lubrication reduces friction and increases efficiency.

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🎡 19. Ideal Machine

An ideal machine has 100% efficiency (no friction or energy loss).

• Impossible in real life due to friction.

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🔋 20. Actual Machine

An actual machine loses some energy due to friction and heat, making efficiency less than 100%.

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🌟 21. Direction of Force

The path along which the force is applied.

• Machines can change the direction of force to make work easier.

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🔥 Example Summary

Machine	Example	Formula	MA
Lever	See-saw	Effort × Effort Arm = Load × Load Arm	Depends on lever type
Pulley	Crane	MA = Number of ropes	2 (movable)
Inclined Plane	Ramp	MA = Length ÷ Height	5
Wheel & Axle	Steering Wheel	MA = Radius of Wheel ÷ Radius of Axle	6
Screw	Bolt	MA = Circumference ÷ Pitch	8
Wedge	Axe	MA = Length ÷ Width	4