CBSE Questions for Class 9 Physics Motion Quiz 8 - MCQExams.com

A displacement-time graph of a body moving with uniform velocity is shown in the figure. Find out its velocity and its displacement at the end of 5 seconds.
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  • 10 m/s, 125 m
  • 5 m/s, 225 m
  • 3m/s, 15 m
  • 15 m/s, 75 m
A ball is thrown vertically upwards from the top of a tower with a velocity of $$\displaystyle { 10\quad ms }^{ -1 }$$. The ball reaches the ground with the velocity $$\displaystyle { 30\quad ms }^{ -1 }$$. What is the height of the tower? $$\displaystyle (Take \quad g ={ 10\quad ms }^{ -2 })$$
  • 40 m
  • 20 m
  • 60 m
  • 80 m
A body whose speed in a particular direction is constant
  • must be accelerating
  • must be retarding
  • has a constant velocity
  • all the above
The final velocity of a body starting from rest and moving with an acceleration $$\displaystyle 2  \ { ms }^{ -2 }$$ and covering a distance of 10 m is _____ $$\displaystyle { ms }^{ -1 }$$.
  • $$\displaystyle \sqrt { 98 } $$
  • $$\displaystyle \sqrt { 40 } $$
  • $$\displaystyle \sqrt { 20 } $$
  • $$\displaystyle \sqrt { 12 } $$
Two bodies of different masses $$ {m} _ {1}$$ and $$ {m} _ {2}$$ are dropped from two different heights $${h} _ {1}$$ and $$ {h} _ {2}$$. What is the ratio of time taken by the two to reach the ground?
  • $$\displaystyle \sqrt { { h }_{ 1 } } :\sqrt { { h }_{ 2 } } $$
  • $$\displaystyle \sqrt { { h }_{ 2 } } :\sqrt { { h }_{ 1 } } $$
  • $$\displaystyle {m} _ {1} {h} _ {2} : {m} _ {2} {h} _ {1} $$
  • $$\displaystyle {m} _ {1} {h} _ {1} : {m} _ {2} {h} _ {2} $$
When brakes are applied the velocity of a car changes from $$\displaystyle { 30\ ms }^{ -1 } to\ { 10\ ms }^{ -1 }$$ in 5 s. The acceleration produced in it is ____ $$\displaystyle { ms }^{ -2 }$$.
  • $$4$$
  • $$-4$$
  • $$20$$
  • $$-20$$
With what speed should a bus travel so that it can cover a distance of 10 km in 5 min?
  • 60 km/hr
  • 10 km/hr
  • 12 km/hr
  • 120 km/hr
A man runs $$20 \  km$$ in $$30 \ min.$$ What is his speed?
  • $$10 \ km/hr$$
  • $$20 \ km/hr$$
  • $$40 \ km/hr$$
  • $$25 \ km/hr$$
If a ball thrown vertically up attains a maximum height of $$80\ m,$$ its initial speed is $$\displaystyle ( g = { 10\ ms }^{ -2 } )$$.
  • $$\displaystyle { 40\ ms }^{ -1 }$$
  • $$\displaystyle { 20\ ms }^{ -1 }$$
  • $$\displaystyle { 50\ ms }^{ -1 }$$
  • $$\displaystyle { 10\ ms }^{ -1 }$$
The velocity of a retarding body changes from $$\displaystyle { 90\ ms }^{ -1 }$$ to $$36\ ms^{ -1 }$$ in $$9$$ seconds. Find the retardation of a body?
  • $$\displaystyle { 20\ ms }^{ -2 }$$
  • $$\displaystyle { 6\ ms }^{ -2 }$$
  • $$\displaystyle { 18\ ms }^{ -2 }$$
  • $$\displaystyle { 36\ ms }^{ -2 }$$
Which of the following formulae is correct?
  • Speed=Distance$$\times $$time
  • Speed=$$\frac { Time }{ Distance } $$
  • Speed=$$\frac { 1 }{ Distance\times time } $$
  • Speed=$$\frac { distance }{ time } $$
A car is travelling at a certain speed. Its final velocity reaches 40 m/s in 10 seconds accelerating at the rate of 2.5 m/s$$\displaystyle ^{2}$$. Find the initial velocity of the car.
  • 20 m/s
  • 0 m/s
  • 15 m/s
  • 10 m/s
A car is travelling at 30 m/s. If its velocity increases to 50 m/s while accelerating at the rate of 2.5 m/s$$\displaystyle ^{2}$$ find the time taken to reach that velocity.
  • 10 s
  • 8 s
  • 4 s
  • 5 s
Calculate the distance travelled by a man walking at a speed of 5 km/hr in 36 minutes.
  • 3 km
  • 4 km
  • 5 km
  • 6 km
When a satellite completes one revolution around the earth its displacement will be zero. True or false
  • True
  • False
The quantity which tells the distance an object travels in a certain time is called -
  • acceleration
  • speed
  • velocity
  • none of these
A stone dropped from the top of a tower reaches the ground with a velocity of 58.8 m/s in 6 seconds. Calculate the value of acceleration due to gravity.
  • 10 m/s$$\displaystyle ^{2}$$
  • 19.6 m/s$$\displaystyle ^{2}$$
  • 8.2 m/s$$\displaystyle ^{2}$$
  • 9.8 m/s$$\displaystyle ^{2}$$
A runner running along a circular track at a constant speed has _______ velocity.
  • Variable
  • Uniform 
  • Potential
  • Parallel
If two bodies are moving with the same speed but in different directions they will have -
  • same velocities
  • same acceleration
  • different velocities
  • none of these
A boy cycles a distance of 640 m in 2 minutes and 40 seconds. What is the speed of the cycle?
  • 4 m/s
  • 8 m/s
  • 12 m/s
  • 16 m/s
Can a moving object cover zero distance?
  • Always
  • Sometimes
  • Never
  • Can't be said from given condition
The velocity of a bullet is reduced from $$200\;\text{m/s}$$ to $$100\;\text{m/s}$$ while travelling through a wooden block of thickness $$10\;\text{cm}$$. Assuming it to be uniform, the retardation will be:
  • $$15\times10^4\;\text{m/s}^2$$
  • $$10\times10^4\;\text{m/s}^2$$
  • $$12\times10^4\;\text{m/s}^2$$
  • $$14.5\;\text{m/s}^2$$
The rate of change of velocity is called speed. True or false.
  • True
  • False
Can, a body in motion, have zero displacement?
  • Yes, always
  • Yes, provided its initial and final positions are same
  • Never
  • Yes, only if its initial and final positions are not same
A ball thrown vertically upwards with a velocity of 15 m/s reaches its highest point at 11.25 m in 1.5 sec. Find the total distance travelled by the ball and its position after 2 sec respectively. Take $$g=10 \ m/s^2$$
  • Total distance = 12 m, After 2 sec = 9.5 m.
  • Total distance = 17.5 m, After 2 sec =7.5 m.
  • Total distance = 14 m, After 2 sec = 9 m.
  • Total distance = 12.50 m, After 2 sec = 10 m.
Speed can be positive, zero or negative. True or false
  • True
  • False
Velocity is the distance travelled by a moving body per unit time. True or false.
  • True
  • False
When brakes are applied to a bus, the retardation produced is  $$25 cm{s}^{-2}$$ and the bus takes $$20s$$ to stop. Calculate the initial velocity of the bus.
  • $$5 m{s}^{-1}$$
  • $$10 m{s}^{-1}$$
  • $$15 m{s}^{-1}$$
  • $$20 m{s}^{-1}$$
A body, initially at rest, starts moving with a constant acceleration $$2 m{s}^{-2}$$. Calculate the distance travelled in 5 s.
  • $$10m$$
  • $$15m$$
  • $$25m$$
  • $$50m$$
A car was moving at $$1 m{s}^{-1}$$ when brakes were applied. The brakes offered a retardation of $$0.5 m{s}^{-2}$$. If the brakes are applied for $$2 s$$, after $$2 s$$
  • the car moves at a reduced speed of $$0.5 m{s}^{-1}$$
  • the car moves at a reduced speed of $$0.25 m{s}^{-1}$$
  • the car stops
  • the car moves with an increased speed of $$2 m{s}^{-1}$$
Find the distance which the car travels before the brakes are applied.
  • $$75m$$
  • $$100m$$
  • $$120m$$
  • $$125m$$
Find the acceleration of the vehicle.
  • $$0.1\ A m{s}^{-2}$$
  • $$0.3\ m{s}^{-2}$$
  • $$0.5\ m{s}^{-2}$$
  • $$1\ m{s}^{-2}$$
A train is moving with a velocity of $$90\ kmph$$. When brakes are applied, the retardation produced is $$0.5\ m{s}^{-2}$$. Find the velocity after $$10 s$$.
  • $$20 m{s}^{-1}$$
  • $$25 m{s}^{-1}$$
  • $$30 m{s}^{-1}$$
  • $$40 m{s}^{-1}$$
A train is moving with a velocity of $$90\  kmph$$. When brakes are applied, the retardation produced is $$0.5 m{s}^{-2}$$. Find the time taken by the train to come to rest.
  • $$20s$$
  • $$30s$$
  • $$40s$$
  • $$50s$$
A car travelling at $$2 m{s}^{-1}$$ undergoes an acceleration of $$1 m{s}^{-2}$$. How long will it take to double its velocity?
  • $$1s$$
  • $$2s$$
  • $$3s$$
  • $$4s$$
A car moving at $$2.5 m{s}^{-1}$$ doubles its velocity with an acceleration of $$0.5 m{s}^{-2}$$ in some time. If the same car travels at $$1.5 m{s}^{-1}$$, what will be its final velocity if same acceleration acts on it for same time?
  • $$2 m{s}^{-1}$$
  • $$3 m{s}^{-1}$$
  • $$4 m{s}^{-1}$$
  • $$5 m{s}^{-1}$$
Distance is
  • the shortest path between the initial and final positions
  • the longest possible path between the initial and final positions
  • the actual path travelled by the body between the initial and final positions
  • none of these
When a body moves in an uniform circular motion, changes in velocity and speed will be
  • velocity changes but speed remains constant
  • velocity remains constant but speed changes
  • both remains constant
  • both changes
The odometer of a car reads $$57321.0 km$$ when the clock shows the time $$08:30$$ AM. What is the distance moved by the car, if at $$08:50 AM$$, the odometer reading has changed to $$57336.0 km$$?
  • $$75\ km$$
  • $$50\ km$$
  • $$15\ km$$
  • $$10\ km$$
Find the total distance travelled.
  • $$460 \ m$$
  • $$4600 \ m$$
  • $$46 \ km$$
  • $$460 \ km$$
A ball is initially moving with a velocity $$0.5 m{s}^{-1}$$. Its velocity decreases at a rate of $$0.05 m{s}^{-2}$$. How much time will it take to stop?
  • $$5s$$
  • $$10s$$
  • $$15s$$
  • $$20s$$
A particle starts to move in a straight line from a point with velocity $$10 m{s}^{-1}$$ and acceleration $$- 2.0 m{s}^{-2}$$. Find the position of the particle at $$t = 5 s$$
  • $$25m$$
  • $$-25m$$
  • $$50m$$
  • $$-50m$$
Larger the slope of a displacement-time graph
  • lesser the velocity
  • higher the velocity
  • lesser the acceleration
  • higher the acceleration
The slope of displacement-time graph being negative implies
  • that the object moves towards the reference point
  • that the object moves away from the reference point
  • that the object is stationary
  • none of these
Velocity, being a vector quantity, positive velocity means
  • that the body is moving away from the reference point
  • that the body is moving towards the reference point
  • that the body is stationary
  • nothing specifically
A bullet emerge from a barrel of length 1.2 m with a speed of $$\displaystyle 640{ ms }^{ -1 }$$. Assuming constant acceleration, the approximate time that it spends in the barrel after the gun is fired is
  • 4 ms
  • 40 ms
  • 400 $$\displaystyle \mu s$$
  • 1 s
If a displacement-time graph of an object is a straight line parallel to the time axis, the object is
  • stationary
  • moving away from the reference point
  • moving towards the reference point
  • moving with an infinite velocity
A vehicle moving with a constant acceleration from $$A$$ to $$B$$ in a straight line $$AB$$, has velocities $$u$$ and $$v$$ at $$A$$ and $$B$$ respectively. $$C$$ is the mid point of $$AB$$. If time taken to travel from $$A$$ to $$C$$ is twice the time to travel from $$C$$ to $$B$$ then the velocity of the vehicle $$v$$ at $$B$$ is:
  • $$5u$$
  • $$6u$$
  • $$7u$$
  • $$8u$$
A car accelerates uniformly so that it goes from a velocity of $$20 {m}/{s}$$ to a velocity of $$40 {m}/{s}$$ in $$5$$ seconds. Find out the acceleration of a car?
  • $$0.2 {m}/{{s}^{2}}$$
  • $$4 {m}/{{s}^{2}}$$
  • $$5 {m}/{{s}^{2}}$$
  • $$10 {m}/{{s}^{2}}$$
  • $$80 {m}/{{s}^{2}}$$
A stone dropped from the top of the tower reaches ground in $$4\ sec$$. Height of the tower is $$(g = 10m/s^{2})$$
  • $$20m$$
  • $$40m$$
  • $$60m$$
  • $$80m$$
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