Solved Examples & Extra Practice

Unit Conversion Practice

Example 1: Converting Large Units

Question: The height of a building is 3250 cm. Express this height in metres.

Solution: We know that: $100 \text{ cm} = 1 \text{ m}$ So, to convert cm to m, we divide by 100.

Example 2: Converting to Small Units

Question: A pencil is 0.12 m long. What is its length in mm?

Solution: First, convert metres to centimetres: $0.12 \text{ m} \times 100 = 12 \text{ cm}$

Next, convert centimetres to millimetres: $1 \text{ cm} = 10 \text{ mm}$ $12 \text{ cm} \times 10 = 120 \text{ mm}$

Answer: 120 mm.

Identifying Motion Types

Example 3: Mixed Motion

Question: A bicycle is moving on a straight road. What types of motion are exhibited by the bicycle?

Solution: There are multiple types of motion happening simultaneously:

1. Linear Motion: The bicycle as a whole is moving forward in a straight line.
2. Circular Motion: The wheels and the pedals are rotating in circles around their axles.

Example 4: The Sewing Machine

Question: Observe a sewing machine in use. Identify the motions.

Solution:

1. Wheel: Undergoes Circular Motion.
2. Needle: Undergoes Oscillatory (Periodic) Motion as it moves up and down rapidly.

Critical Thinking

Example 5: Broken Scale

Question: You have a ruler where the tip is broken. You start measuring an eraser from the mark $3.0 \text{ cm}$ and the eraser ends at the mark $7.6 \text{ cm}$. What is the length of the eraser?

Solution: