# Directorate of GNCT of Delhi Class 9 Worksheet 39 Subject: Science

DoE GNCT of Delhi Class 9 Worksheet 39 Science Solution

## Class 9 Worksheet 39 Science Question and Answer:

### Q1. Define Inertia

Ans: The natural tendency of an object to resist a change in their state of uniform motion or of rest is called inertia. Every object opposes the changes in its state of motion or rest.

### Q2. Write first law of motion with example.

Ans: Laws of motion including first law are given by Newton. According to first law of motion "An object remains in a state of rest or of uniform motion in straight line unless acted upon by an unbalanced force". This law is also called as law of inertia.

Example: we feel jerk in forward direction when breaks are applied suddenly on the moving bus or car.

### Q.3 In which direction the passengers will feel jerk, if the bus starts moving suddenly? Explain

Ans: Backward direction

When a bus at rest starts, to move suddenly, the passengers sitting in it jerk in backward direction due to their inertia of rest.

### Q.4 Which will have more inertia:

Ans: A bus

#### b) a bicycle and a motorcycle

Ans: A Motorcycle

#### c) a cart and a train

Ans: A Train

Note: As per law of inertia heavier object will have larger inertia in comparison to the lighter object.

Also Read: Worksheet 39 Hindi Solution