MCQ Questions for Class 7 Physics Motion And Time Quiz 2

A dancer demonstrating dance steps along a straight line. The position time graph is given. Find the average velocity for the dance step depicted by AB.

0%
$1 m s^{-1}$
0%
$1.33 m s^{-1}$
0%
$2.75 m s^{-1}$
0%
$0 m s^{-1}$

Explanation

For the dance step depicted by AB :
Path length

$=$ 0;
Displacement

$=$ 0
Time taken, t

$=$ 1 s
Average velocity

$= \displaystyle \dfrac{displacement}{time \ taken}$

$\displaystyle = \dfrac{0}{1} =0$

Speed of a body depends on

0%
Time
0%
Mass of the body
0%
Distance travelled by the body
0%
Both A and C

Explanation

Speed is defined as

$Speed = \dfrac{\text{Distance travelled}}{\text{Time interval}}$

Hence speed depends both on time and distance travelled by the body.

So both A and C are correct.

0%
Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
0%
Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
0%
Assertion is correct but Reason is incorrect
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Assertion is incorrect but Reason is correct

Explanation

We know that 1 decade is equal to 10 years.

So,

$100 \ years = \dfrac{100 }{10} \ decades = 10 \ decades$

So, the assertion statement is true.

Reaon statement is also true and it explains the assertion very well.

Name one unit of time bigger than a second.

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plank time
0%
zeptosecond
0%
picosecond
0%
kilosecond

Explanation

$1\ kilosecond=1000\ seconds$

Rain is falling vertically with a speed of 1.7 m/s. A girl is walking with speed of 1.0 m/s in the N - E (north-east) direction. To shield herself she holds her umbrella making an approximate angle

$\theta$ with the vertical in a certain direction. Then

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$\theta=60^0 \:in \:N - E \:direction$
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$\theta=30^0 \:in \:N - E \:direction$
0%
$\theta=60^0 \:in \:S - W \:direction$
0%
$\theta=30^0 \:in \:S - W \:direction$

What is a leap year ?

0%
$366$ days
0%
$365$ days
0%
$364$ days
0%
$363$ days

A dancer demonstrating dance steps along a straight line. The position-time graph is given below.

Find the average velocity of the dancer during the time interval between t

$=$ 4.5 s to t

$=$ 9 s

0%
$1 m s^{-1}$
0%
$-1.33 m s^{-1}$
0%
$2.75 m s^{-1}$
0%
$-0.89 m s^{-1}$

Explanation

Displacement = final position - initial position

From graph final position is zero at

$9\ s$ .

From graph initial position is

$4\ m$ at

$4.5\ s$ .

Here, displacement

$=-4\ m$
Time taken,

$t=9-4.5$

$\Rightarrow t = 4.5\ s$

Average velocity

$(V_{avg})$

$V_{avg} \displaystyle = \dfrac{displacement}{time}$

$\Rightarrow V_{avg}= \displaystyle \dfrac{-4}{4.5}$

$\Rightarrow V_{avg} = -0.89 m s^{-1}$

Which of the following relations is correct?

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Speed = $\frac { 1 }{ Distance\times Time }$
0%
Speed = $\frac { Time }{ Distance }$
0%
Speed = $\frac { Distance }{ Time }$
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Speed = Distance $\times$ Time

Explanation

Speed is defined as the distance travelled by an object per unit time.

$Speed = \dfrac{Distance}{time}$

Which of the following is not in uniform motion?

0%
A bullet travelling with a constant speed in a straight line.
0%
A swinging pendulum
0%
The earth rotating about its axis
0%
Both B & C

Explanation

$A-$ As the bullet has a constant speed and is travelling in a straight line, so it will have a constant velocity and hence it is in uniform motion

$B-$ A swinging pendulum is under the action of gravitational force and is also changing its direction, hence it is not in uniform motion.

$C-$ The rotation of the earth in non accelerated motion and hence it is a uniform motion

Hence, correct answer is option

$B$

Which of the following is NOT matched correctly?

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Speedometer: Speed
0%
Odometer : Odour
0%
Anemometer : Wind speed
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Stopwatch : Time

Fill in the blank:

$1$ mean solar day = _____

$s$ .

0%
$43200$
0%
$86636$
0%
$21600$
0%
$10800$

Explanation

A solar day is the time it takes for the Earth to rotate about its axis so that the Sun appears in the same position in the sky, which is equal to

$24\ hr\ 03\ min\ 55\ s$ , i.e. in total,

$86636\ seconds$ .

What is the value of

$1$ nano-second in second?

0%
$10^{-9}$
0%
$10^{-6}$
0%
$10^{-8}$
0%
$10^{-10}$

Explanation

A nanosecond (

$ns$ ) is an SI unit of time equal to one billionth of a second . One nanosecond is to one second as one second is to

$31.71\ years$ . The word nanosecond is formed by the prefix nano and the unit second. Its symbol is

$ns$ .

With what speed should a car travel so that it can cover a distance of 5 km in 5 min?

0%
1 km/h
0%
5 km/h
0%
12 km/h
0%
60 km/h

Explanation

Given,

Distance cover

$d=5\ km$

Time

$t=5\ min$ or

$t=5/60\ hr$

Speed

$v=\dfrac{5}{5/60}=60\ km/hr$

Option D

A man runs

$10 \ km$ in

$30 \ min.$ What is his speed?

0%
$5 \ km/h$
0%
$10 \ km/h$
0%
$15 \ km/h$
0%
$20 \ km/h$

Explanation

We know that,

$Speed = \dfrac{distance}{time}$

Given:

Distance

$=10 \ km$

Time

$=30 min= \dfrac{30}{60} \ hr=0.5 \ hr$

Speed

$=\dfrac{10 \ km}{0.5 \ hr} = 20 \ km/h$

Option D is the answer.

Which one of the following is travelling with the fastest speed?

0%
An athlete running with a speed of 10 m/s
0%
A bicycle moving with a speed of 200 m/min
0%
A tortoise covering 100 metres in 15 minutes
0%
A motorcycle moving with a speed one km/h

Explanation

To get the correct answer,we need to convert each speed in same unit i.e. m/s
A)An athlete running with a speed of 10 m/s
B)A bicycle moving with a speed of 200 m/min it can be written as

$=\frac{200}{60}m/s$

$=3.33m/s$
C)A tortoise covering 100 metres in 15 minutes

$=\frac{100}{15}m/min$

$=\frac{100}{{15}\times{60}}m/s$

$=0.11m/s$
D)A motorcycle moving with a speed one km/h

$=1km/h$

$=\frac{1000}{{1}\times{60}\times{60}}$

$=0.27m/s$
Comparing A, B, C, and D one can easily say that answer is option A i.e.
An athlete running with a speed of 10 m/s is the fastest.

Find the odd one out:

0%
Solar day
0%
Moon day
0%
Second
0%
Light year

The cheetah is the fastest land animal that can attain a maximum speed of

$112~ km/h$ . Express this speed in

$m/s$ .

0%
$31 ~m/s$ (approx.)
0%
$30 ~m/s$ (approx.)
0%
$32 ~m/s$ (approx.)
0%
$29 ~m/s$ (approx.)

Explanation

Given,

The maximum speed by the cheetah,

$v=112\ km/h$

We know,

$1\ km=1000\ m$

$1\ h=60\ min$

$1\min=60\ s$

$\therefore 1\ h=60\times 60=3600\ s$

$v=\dfrac{112\times 1000}{3600}$

$v=31.1\ m/s$

The odometer of a car reads

$57321.0\ km$ when the clock shows the time 8:30 AM. The distance moved by car if, at 8:50 AM, the odometer reading has changed to

$57336.0\ km$ and also the speed will be:

0%
$15\ km ,\ 45\, km/h$
0%
$10km ,$ $45\, km/h$
0%
$15km ,$ $55\, km/h$
0%
$20km ,$ $45\, km/h$

Explanation

Time from $8.30$ $AM$ to $8.50$ $AM$ = $20$ $min$

$20min=(20/60)h=(1/3)h$

(a) Distance covered = Second reading - First reading = $57336.0$ $km$ - $57321.0$ $km$ = $15$ $km$

(b) $Speed=\dfrac{Distance}{Time}$ = $\dfrac{15}{1/3}$ = $45km/h$

The rear view mirror of a car is a plane mirror. A driver is reversing his car at a speed of 2 m/s. The driver sees in his rear view mirror the image of a truck parked behind his car. The speed at which the image of the truck appears to approach the driver will be ________________.

0%
1 m/s
0%
2 m/s
0%
4 m/s
0%
8 m/s

Which of the following is not the unit of time ?

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Micro second
0%
Leap year
0%
Lunar months
0%
Parallactic second

A boy running at an average speed of

$4 km/ hr$ reaches school from his home in

$\dfrac{1}{2}\ hr$ . The distance of the school from his home is

0%
$2 km$
0%
$8 km$
0%
$4 km$
0%
$6 km$

Explanation

Given:

Average speed of the boy

$v =4\ km/h$
Time taken

$t =\dfrac{1}{2}$ hour

Distance

$D=?$

We know that

$Speed(v)=\dfrac{Distance(D)}{Time(t)}$

$\Rightarrow Distance(D)=4\times\dfrac{1}{2}$

$\Rightarrow Distance(D)=2\ km$

What does the speed of a body describes about its motion ?

0%
Direction
0%
State
0%
Type
0%
Rapidity

Explanation

$speed =\frac{distance}{time}$ Speed tells us how fast or slow the distance is being covered by the moving body .Hence it denotes it's rapidity(Means how rapid the moving object is).

The SI unit of speed is:

0%
$m/s$
0%
$km/s$
0%
$cm/s$
0%
None of these

Explanation

The distance moved by an object in a unit time is known as speed.

The SI unit of speed is

$m/s$ .

Which of the following graphs represents the movement of a car that is slowing down and comes to a complete stop?

Calculate the distance travelled by a man walking at a speed of 5 km/hr in 36 minutes.

0%
3 km
0%
4 km
0%
5 km
0%
6 km

Explanation

Given s = 5km/hr = 5

$\displaystyle \times \frac{5}{18}m/s$
t = 36 minutes = 36

$\displaystyle \times$ 60 sec

$\displaystyle \therefore$ distance travelled = s

$\displaystyle \times$ t
=

$\displaystyle \frac{25}{18}\times 36\times 60 = 3000 m$
=

$\displaystyle \frac{3000}{1000}km = 3 km$

How many seconds are there in 12 hours?

0%
12 seconds
0%
720 seconds
0%
43200 seconds
0%
432000 seconds
0%
None of these

Explanation

Total seconds in

$12\ hours$ -

Total minutes in one hour,

$1\ h = 60\ min$

Total seconds in one min,

$1\ min = 60\ s$

So,

$12\ h = 12 \times 60 \times 60\ s$

$\Rightarrow 12\ h = 12 \times 3600 \ s$

$\Rightarrow 12\ h = 43200\ s$

The rate of change of velocity is called speed. True or false.

0%
True
0%
False

With what speed should a bus travel so that it can cover a distance of 10 km in 5 min?

0%
60 km/hr
0%
10 km/hr
0%
12 km/hr
0%
120 km/hr

Explanation

$60$

$min$ =

$1hour$

$5$

$min$ =

$\dfrac { 1 }{ 60 } \times 5=\dfrac { 1 }{ 12 } h$

$Speed$ =

$\dfrac { Distance }{ Time }$

$Distance=10km$

$time=\dfrac{1}{12}h$

$speed$ =

$\dfrac { 10 }{ \dfrac { 1 }{ 12 } }$ =

$10\quad \times \quad 12$
=

$120$

$km/h$

A man runs

$20 \ km$ in

$30 \ min.$ What is his speed?

0%
$10 \ km/hr$
0%
$20 \ km/hr$
0%
$40 \ km/hr$
0%
$25 \ km/hr$

Explanation

Given:

Distance

$= 20 \ km$

Time

$=30 \ min =\dfrac{30}{60}hr= \dfrac { 1 }{ 2 } hr$

$\therefore$ Speed =

$\dfrac { Distance }{ time }$ =

$\dfrac { 20 \ km}{ \left( \dfrac { 1 }{ 2 }hr \right) }$

$\Rightarrow$ Speed

$=40 \ km/hr$

Option (C) is correct.

Which is not a necessary assumption for simple pendulum

0%
in-extensible, light and flexible string.
0%
heavy but small sized sphere (bob).
0%
angular displacement from the mean position is very less.
0%
volume of the bob is negligible.

CBSE Questions for Class 7 Physics Motion And Time Quiz 2 - MCQExams.com

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Practice Class 7 Physics Quiz Questions and Answers

CBSE Questions for Class 7 Physics Motion And Time Quiz 2 - MCQExams.com

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Practice Class 7 Physics Quiz Questions and Answers

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