# NCERT Solutions for Class 7th Science

## Chapter 13. Motion and Time

### Additional Questions With solutions

### Additional Questions With solution:

**Ques: – Define speed.**

**Ans: –** We call the distance covered by an object in a unit time as the speed of the object.

**Ques: – What is non-uniform motion?**

**Ans: – **If the speed of an object moving along a straight line keeps changing, its motion is said to be non-uniform.

**Ques: – What is uniform motion?**

**Ans: –** An object moving along a straight line with a constant speed is said to be in uniform motion.

**Ques: – Define time period?**

**Ans: –** The time taken by the pendulum to complete one oscillation is called its time period.

**Ques: – What is the bob of the pendulum?**

**Ans: –** The metallic ball is called the bob of the pendulum.

**Ques: – What is periodic or an oscillatory motion?**

**Ans: –** The to and fro motion of a simple pendulum is an example of a periodic or an oscillatory motion.

**Ques: – Name the basic unit of time.**

**Ans: –** The basic unit of time is a second.

**Ques: – What tells the speedometer of a car?**

**Ans: –** Speed.

**Ques: – What tells the odometer of a car?**

**Ans:–** Distance.

**Ques: – What is odometer?**

**Ans: –** Another meter that measures the distance moved by the vehicle. This meter is known as an odometer.

**Ques: – A simple pendulum takes 32 s to complete 20 oscillations. What is the time period of the pendulum?**

**Ans: - **

**Ques :– The distance between two stations is 240 km. A train takes 4 hours to cover this distance. Calculate the speed of the train.**

**Ans :–**

Distance = 240 km

Taken time = 4 hours

**Ques :– Salma takes 15 minutes from her house to reach her school on a bicycle. If the bicycle has a speed of 2 m/s, calculate the distance between her house and the school.**

Ans :-