YEAR 4 SCIENCE CHAP 10

Machines are here to

• Increase the cost of production

• Help humans work more easier

• Destroy the human's nature

• Making work more difficult

A blender consists of wedge, screw, and gear.

• True
• False

Answer explanation

A blender consists of wedge (blades), gear and screws (motor parts)

A simple machine is a tool that enables us to do things faster and easier.

• True

• False

Which of the following below are the types of simple machines?

• Blender

• Screw

• Ceiling fan

• Inclined plane

Answer explanation

There are 7 types of simple machines such as wheel and axle, gear, screw, pulley, inclined plane, wedge and lever.

Which of the following are complex machines?

• Hammer

• Car

• Knife

• Water dispenser

Answer explanation

A complex machine consists of a series/combination of simple machines

What is a sustainable machine?

• A machine that costs a lot of money to purchase

• A machine that are harmful to environment

• A machine that burdens the human

• A machine that are high in durability and save for environment

Answer explanation

Sustainable machines are machines that are high in durability, easy to use, not easily damaged, does not harm the environment and the users and profitable.

Machine makes human to save energy and time.

• True
• False

A sharpener consists of combination of simple machines such as

• Wedge, gear and pulley

• Wedge and screw

• Pulley and gear

• Inclined plane and lever

Answer explanation

A sharpener has wedge (blade) and screw (to fix the blade).

Which of the following are the examples of pulley?

• Water well

• Hammer

• Bulldozer

• Bicycle

Answer explanation

A pulley consists of a wheel with a groove that allows a rope to pass through it to lift/lower the load.

Which of the following are the examples of screw?

• Door

• Bulb

• Wood plank

• Book