Unit - 3 Simple Machine

 Unit - 3

Simple Machine

Practice

1. Fill in the blank

(a) It is better to cut cloth with scissors than to cut cloth by hand.

(b) Penchis is a wedge.

(c) Work can be done by using a stove.

(d) It helps to make work easier in daily life.

(e) When a simple device works, it changes the direction of force.

2. Choose one correct answer from the given answers

(a) What is called a simple device?

A device to facilitate work

Devices to assist in speedy completion of work

A device for completing work quickly and easily

👉 All of the above.

(b) Which of the following is not a simple device?

Bhayang

 A wheelbarrow

Ghirni

👉 Electric stick

(d) In which case the lever exerts more force than the applied force?

The distance of load is longer

Distance of force is longer

Distance between load and force is greater

 👉 Load and force are closer

3. Write the answers to the following questions:

(a) Which device is called a simple device?

👉 A simple device is a machine that has few or no moving parts and is used to change the direction or magnitude of a force.

(b) Name any five simple devices.

👉 Some examples of simple devices include:

• Inclined plane
• Lever
• Wedge
• Wheel and axle
• Pulley

(c) List three uses of a simple device.

👉 Simple devices can be used to:

• Change the direction of a force
• Increase the force applied to an object
• Reduce the distance over which a force must be applied

(d) Write one function of scissors, axe, chisel, needle and hammer.

👉 Scissors are used to cut objects.

• Axes are used to chop wood.
• Chisels are used to carve wood or stone.
• Needles are used to sew fabric.
• Hammers are used to drive nails or other objects into wood or other materials.

(e) Simple devices prevent risks at work. Confirm that statement.

👉 Simple devices can help to prevent risks at work by:

• Making it easier to lift heavy objects
• Providing a better grip on slippery surfaces
• Reducing the risk of cuts and other injuries

(f) For which tasks are simple devices used in your home? any three

👉 Simple devices are used in homes for a variety of tasks, including:

• Opening doors and windows
• Turning on and off lights
• Lifting heavy objects
• Moving furniture
• Cooking food

(g) It is better to lift a heavy object with the neck than to lift it with the hand. of this

👉 Confirm with two reasons.

It is not better to lift a heavy object with the neck than to lift it with the hand. In fact, it is much safer to lift heavy objects with the hands. Here are two reasons why:

Lifting heavy objects with the neck can put a lot of strain on the neck muscles and ligaments.

Lifting heavy objects with the neck can also cause the head to tilt back, which can restrict the airway and make it difficult to breathe.