Motion and Time Class 7 Extra Questions and Answers Science Chapter 13 PDF are solved by experts and will guide students in the right direction. Students can get how to tackle different questions easily by solving the Extra Questions for Class 7 Science Question bank on a regular basis.

## Class 7 Science Chapter 13 Extra Questions and Answers Motion and Time

**Extra Questions for Class 7 Science Chapter 13 Motion and Time with Answers**

### Motion and Time Class 7 Extra Questions Very Short Answer Type

Question 1.

Write formula for speed.

Answer:

Speed = \(\frac{\text {Total distance travelled}}{\text {total time taken}}\)

Question 2.

Define a day.

Answer:

The time between one sunrise and the next is called a day.

Question 3.

What is a year?

Answer:

A year is fixed as the time taken by the earth to complete one revolution around the sun.

Question 4.

What is a month?

Answer:

A month is measured from one new moon to the next.

Question 5.

What is bob?

Answer:

The metallic ball hanging with the thread is called the bob of the pendulum.

Question 6.

What is oscillatory motion?

Answer:

The to and fro motion of an object is called periodic or an oscillatory motion of that object.

Question 7.

What is speedometer?

Answer:

It is a device that is used to measure speed directly in km/h.

Question 8.

What is odometer?

Answer:

Meter that measures the distance moved by the vehicle is known as an odometer.

### Motion and Time Class 7 Extra Questions Short Answer Type 1

Question 1.

“Speed of a car is 50 km/h.” What does it mean?

Answer:

When we say that a car is moving with a speed of 50 kilometres per hour, it implies that it will cover a distance of 50 kilometers in one hour.

Question 2.

What are microseconds and nano-second?

Answer:

One microsecond is one-millionth of a second. A nanosecond is one-billionth of a second.

Question 3.

Name different types of graphs.

Answer:

Bar graph, line graph, pie graph.

### Motion and Time Class 7 Extra Questions Short Answer Type 2

Question 1.

How is speed of car in non-uniform motion measured?

Answer:

The speed is calculated as the total distance covered divided by the total time taken. Thus,

speed = \(\frac{\text {Total distance covered}}{\text {Total time taken}}\)

This is called average speed.

### Motion and Time Class 7 Extra Questions Long Answer Type

Question 1.

Suggest some points to be kept in mind while choosing the most suitable scale for drawing a graph.

Answer:

Some of the points to be kept in mind while choosing the most suitable scale for drawing a graph are:

- the difference between the highest and the lowest values of each quantity.
- the intermediate values of each quantity, so that with the scale chosen it is convenient to mark the values on the graph, and
- to utilize the maximum part of the paper on which the graph is to be drawn.

Question 2.

A ball moves 30 m in 6s. Find its speed.

Answer:

Here, d = 30 m

t = 6 s

s = ?

We know,

s = \(\frac {d}{t}\)

= \(\frac {30m}{6s}\) = 5 ms^{-1}

Question 3.

A body is moving with a speed 10 m/s. After 1 minute, what is the distance traveled?

Answer:

Here, s = 10 m/s

t = 1min = 60 s

d = ?

we know,

s = \(\frac {d}{t}\)

⇒ d = s.t

= 10 m/s × 60 s

= 600 m

Question 4.

Find the distance covered by a car moving at 50 km/h in 2 hours.

Answer:

Given, s = 50 km/h

t = 2 h

d = ?

We know that,

s = \(\frac {d}{t}\)

or, d = st

= 50 km/h × 2 h

= 100 km

Question 5.

The bowling speed of Shoaib Akhtar is 144 km/h. Find in what time the ball reaches the batsman. Consider that the batsman is standing at a distance 20 m from the bowling crease.

Answer:

Given,

Question 6.

Write briefly about the development of pendulum clock.

Answer:

It is said that once Galileo (AD 1564 – 1642) was sitting in a church. He noticed that a lamp suspended from the ceiling with a chain was moving slowly from one side to the other. He was surprised to find that his pulse beat the same number of times during the interval in which the lamp completed one oscillation.

Galileo experimented with various pendulums to verify his observation. He found that a pendulum of a given length takes always the same time to complete one oscillation. This observation led to the development of pendulum clocks. Winding clocks and wristwatches were refinements of the pendulum clocks.

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