Motion And Time(7th Grade > Physics ) Questions and answers for exam Preparation

7th Grade > Physics

MOTION AND TIME MCQs

Total Questions : 115 | Page 1 of 12 pages

Question 1. A train is moving at a constant speed.
If the train covers

50 k m

2

hours, how much time would it take to cover

100 k m

Discuss Question

Answer: Option D. -> 4 h
:
D
Given:
Distance travelled in

2 h = 50 k m

.
Speed =

\frac{Distance}{Time}

\Rightarrow

Speed = \frac{50}{2}

= 25

k m h^{- 1}

Now, to travel

100 k m

at the same speed as given above,
Speed

= 25 k m h^{- 1}

= \frac{Distance}{Time}

\Rightarrow

Time

= \frac{100 k m}{25 k m h^{- 1}}

\Rightarrow

Time

= \frac{100}{25} = 4 h

Question 2. The position-time graph of a body is a straight line parallel to the X-axis. What does this imply?

The body is at rest.
The body is in uniform motion.
The body is in non-uniform motion.
The body is in periodic motion.

Discuss Question

Answer: Option A. -> The body is at rest.
:
A
In a position-time graph, the X-axis indicates time and the Y-axis indicates the position.
If the graph is a straight line parallel to the X-axis, it means that the position of the body is the same at different intervals of time.
This can happen only when the body is at rest.

The Position-time Graph Of A Body Is A Straight Line Paralle...

Question 3. When do you call an object to be moving? [1 MARK]

Discuss Question

:
Motion definition: 1 Mark
If the position of the body is changing with time, with respect to an observer, then thebody is said to be in motion.

When Do You Call An Object To Be Moving? [1 MARK]

Question 4. A boy is driving a car at a speed of 60 km/hr from his home to college. In the return journey, his speed was half of what it was in the ongoing journey. Calculate the total time of the entire journey. Given: Distance between college and home is 12 km. Also, find the average speed of the car for the entire journey. [5 MARKS]

Discuss Question

:
Distance: 2 Marks
Average Speed: 1 Mark
Formula: 1 Mark
Steps: 1 Mark
From home to school:
Speed of car = 60 km/hr
Distance = 12 km
Time taken

= \frac{d i s t a n c e}{s p e e d} = \frac{12}{60} = 0.2 h r s

From school to home:
Speed of car

= \frac{60}{2}

= 30 km/hr
Distance = 12 km
Time taken

= \frac{12}{30} = \frac{2}{5} = 0.4 h r s

Total time taken by car = 0.2 + 0.4 = 0.6 hrs
Average Speed

= \frac{T o t a l D i s t a n c e t r a v e l l e d}{T o t a l T i m e}

= \frac{24}{0.6}

= 40 km/hr

Question 5. Define the following:
1) Rectilinear motion
2) Circular motion
3) Curvilinear motion [3 MARKS]

Discuss Question

:
Sub-parts: 1 Mark each
1) Motion along a straight line is known as rectilinear motion.

Define The Following:1) Rectilinear Motion2) Circular Mo...

2) Motion along a circle is known as circular motion.

3) Motion along a curved line is known as curvilinear motion.

Question 6. The odometer of a vehicle has an initial reading of

22256 k m

. After the trip, it shows a reading of

22356 k m

. If the time taken for the trip is

5

hours, what is the average speed of the vehicle?

20 km h−1
30 km h−1
40 km h−1
50 km h−1

Discuss Question

Answer: Option A. -> 20 km h−1
:
A
Given:
Odometer reading, before the trip

= 22256 k m

.
Odometer reading, after the trip

= 22356 k m

.
So the distance travelled in the trip

= 22356 - 22256 = 100 k m

.
Time taken for the trip

= 5 h

.
Average speed =

\frac{Total distance travelled}{Total time taken}

∴

Average speed

= \frac{100}{5} = 20 k m h^{- 1}

Question 7. The S.I unit of distance is kilometre.

True
False
To the left
To the right

Discuss Question

Answer: Option B. -> False
:
B
The S.I unit of distance is metre, not kilometre.

Question 8. If the speed of a car is

20 m s^{- 1}

, what is the speed in

k m h^{- 1}

Discuss Question

Answer: Option B. -> 72
:
B
Given that the speed of a car

= 20 m s^{- 1}

= \frac{20 m}{1 s}

[

1 m = \frac{1}{1000} k m, 1 s = \frac{1}{3600} h

]

= \frac{20 \times \frac{1}{1000} k m}{1 \times \frac{1}{60 \times 60} h}

= \frac{20 \times 3600}{1000} k m h^{- 1}

= 72 k m h^{- 1}

Question 9. If a body is moving in a straight line but it keeps changing its speed, then the motion of the body is _____.

non-uniform
uniform
periodic
circular

Discuss Question

Answer: Option A. -> non-uniform
:
A
When a body is moving in a straight line and its speed changes frequently, it implies that the bodywill cover unequal distances in equal intervals of time. Hence this is a non-uniform motion.

Question 10. Calculate the distance travelled by the object at a speed of 15