CBSE Questions for Class 9 Physics Motion Quiz 5 - MCQExams.com

State whether given statement is True or False.
A body can have constant velocity and still have varying speed?
  • True
  • False
A driver applies brakes when he sees a child on the railway track, the speed of the train reduces from $$54\ kmph$$ to $$18\ kmph$$ in $$5\ s$$. What is the distance traveled by train during this interval of time?
  • $$52\ m$$
  • $$50\ m$$
  • $$25\ m$$
  • $$80\ m$$
The speed of a car reduces from $$15  m  s^{-1} $$ to  $$5  m  s^{-1}$$ over a displacement of 10 m. What is the uniform acceleration of the car?
  • $$-10 m s^{-2}$$
  • $$+10 m s^{-2}$$
  • $$2 m s^{-2}$$
  • $$0.5 m s^{-2}$$
To reach the same height on the moon as on the earth, a body must be projected up with:
  • Higher velocity on the moon
  • Lower velocity on the moon
  • Same velocity on the moon and earth
  • It depends on the mass of the body
A particle is thrown vertically upwards. Its velocity at one fourth of the maximum height is $$20 \ m s^{-1}$$. Then, the maximum height attained by it is
  • 16 m
  • 10 m
  • 8 m
  • 18 m
A stone thrown vertically upwards with an initial velocity u from the top of a tower reaches the ground with a velocity of 3 u. The height of the tower is :
  • $$3 \displaystyle \dfrac{u^2}{g}$$
  • $$4 \displaystyle \dfrac{u^2}{g}$$
  • $$6 \displaystyle \dfrac{u^2}{g}$$
  • $$9 \displaystyle \dfrac{u^2}{g}$$
A ball is thrown vertically upwards. It has a speed of $$10  m  s^{-1}$$, when it has reached on half of its maximum height. How high does the ball rise? (Take g $$=$$ 10 m s$$^{-2}$$)
  • 10 m
  • 5 m
  • 15 m
  • 20 m
A body having zero speed :
  • Is always under rest.
  • Has always zero acceleration.
  • Has always uniform acceleration.
  • Always under motion.
A ball is released from the top of height 'h' meters. It takes 't' seconds to reach the ground. Where is the ball at the time $$\displaystyle \dfrac{t}{2} s$$ ?
  • At $$\displaystyle \left ( \dfrac{h}{4} \right) $$ from the ground
  • At $$\displaystyle \left ( \dfrac{h}{2} \right) $$ from the ground
  • At $$\displaystyle \left ( \dfrac{3h}{4} \right) $$ from the ground
  • Depends upon mass and volume of the ball
A body thrown vertically up reaches a maximum height of 50 m. Another body with double the mass is thrown up with double the initial velocity will reach a maximum height of :
  • 100 m
  • 200 m
  • 400 m
  • 50 m
Two balls are dropped from heights $$h_1$$ and $$h_2$$ respectively. The ratio of their velocities on reaching the ground is __________ .
  • $$\sqrt{h_1} : \sqrt{h_2}$$
  • $$h_1 : h_2$$
  • $$h^2_1 : h^2_2$$
  • none of these
Displacement of a particle moving in a circle at any two different instants of time is zero.
  • True
  • False
A body moving in a straight line can have a constant velocity with varying speed.
  • True
  • False
The ratio of the heights from which two bodies are dropped is 3 : 5 respectively. The ratio of their final velocities is?
  • $$\sqrt{5} : \sqrt{3}$$
  • $$\sqrt{5} : \sqrt{2}$$
  • $$\sqrt{3} : \sqrt{5}$$
  • none of the above
A freely falling body travels with uniform acceleration .
  • True
  • False
A car attains a velocity of 10 m s$$^{-1}$$ in 5 s. If initially, it had been at rest, its acceleration must be ___________ .
  • 50m s$$^{-2}$$
  • 2 m s$$^{-2}$$
  • 5 m s$$^{-2}$$
  • 0.6 m s$$^{-2}$$
If a body starts from rest and moves with uniform acceleration, then the displacement of the body is directly proportional to the cube of the time.
  • True
  • False
A body falling for 2 s, covers a distance equal to that covered in the next second. State whether true or false
  • True
  • False
The displacement - time graphs of two bodies $$A$$ and $$B$$ are $$OP$$ and $$OQ$$ respectively. Velocities of A and B are related as 
123222.png
  • $$V_A > V_B$$
  • $$ V_A < V_B $$
  • $$V_A = V_B $$
  • Cannot Predict
A point moves rectilinearly in one direction. Above figure shows the distance $$s$$ traversed by the point as a function of the time $$t$$. Using the plot, find the maximum velocity.
128963_d640f9e14bde4ab0919a61a9a1ba7612.png
  • $$1.5\:m/s$$
  • $$2.5\:m/s$$
  • $$2 \:m/s$$
  • $$5\:m/s$$
A car is moving in a straight line. The position time graph $$(x-t)$$ is as shown in the given figure. Find the average speed of the car for the section- CD.
120572.png
  • $$1\ ms^{-1}$$
  • $$2.66\ ms^{-1}$$
  • $$3\ ms^{-1}$$
  • $$0.89\ ms^{-1}$$

120591.png
  • Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
  • Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
  • Assertion is correct but Reason is incorrect.
  • Assertion is incorrect but Reason is correct.
At which instant do the two cars have the same velocity?
132668.png
  • $$ t_1 $$
  • $$ t_2 $$
  • $$ t_3 $$
  • $$ t_4 $$
Which one of the following best describes the motion of car A as shown on the graphs?
132668.png
  • Speeding up
  • Constant velocity
  • Slowing down
  • First speeding up, then slowing down
A balloonist is ascending at a velocity of $$12\ m{ s }^{ -1 }$$. A packet is dropped from it when it is at height of $$65 \ m$$ from the ground. Time taken by the packet to reach the ground is
  • $$5 \ s$$
  • $$-5 \ s$$
  • $$7 \ s$$
  • $$\cfrac{13}{5} \ s$$
A parachutist after bailing out falls $$50\ m$$ without friction. When parachute opens, it decelerates at $$2\ m{ s }^{ -2 }$$. He reaches the ground with speed $$3\ m{ s }^{ -1 }$$. At what height did he bail out?
($$g=9.81m/{ s }^{ 2 }$$)
  • $$91\ m$$
  • $$182\ m$$
  • $$293\ m$$
  • $$111\ m$$
An object may have
(I) varying speed without having varying velocity.
(II) varying velocity without having varying speed.
(III) non-zero acceleration without having varying velocity.
(IV) non-zero acceleration without having varying speed.
  • I and II are correct.
  • II and III are correct.
  • II and IV are correct.
  • None of the above.
The muzzle velocity of a certain rifle is $$330\ m{ s }^{ -1 }$$. At the end of one second, a bullet fired straight up into the air will travel a distance of
  • $$(330-4.9)\ m$$
  • $$330\ m$$
  • $$(330+4.9)\ m$$
  • $$(330-9.8)\ m$$
When a ball is $$h$$ metre high from a point $$O$$, its velocity is $$v$$. When it is $$h\ m$$ below $$O$$, its velocity is $$2v$$. Find the maximum height from $$O$$ it will acquire.

133771_9ca68c8911f743b886a0e8c8fda2774e.jpg
  • $$\cfrac { 2h }{ 3 } $$
  • $$\cfrac { 5h }{ 3 } $$
  • $$\cfrac { 3h }{ 2 } $$
  • $$2h$$
Which of the following statements are true for a moving body?
  • If its speed changes, its velocity must change and it must have some acceleration.
  • If its velocity changes, its speed must change and it must have some directions.
  • If its velocity changes, its speed may or may not change, and it must have some acceleration.
  • If its speed changes but direction of motion does not change, its velocity may remain constant.
A bullet, moving with a velocity of $$200cm/s$$ penetrates a wooden block and comes to rest after traversing $$4cm$$ inside it. What velocity is needed for traversing a distance of $$6cm$$ in the same block
  • $$104.3cm/s$$
  • $$136.2cm/s$$
  • $$244.9cm/s$$
  • $$272.7cm/s$$
The first stage of the rocket launches a satellite to a height of $$50\ km$$ and velocity attained is $$6000\ km{ h }^{ -1 }$$ at which point its fuel exhausted. How high the rocket will reach (Take $$g=10\ m/s^2$$ and assume $$g$$ is constant up to for rocket's entire journey?
  • $$138.9\ km$$
  • $$188.9\ km$$
  • $$88.9\ km$$
  • $$168.9\ km$$
When a ball is thrown up vertically with a velocity $${ v }_{ 0 }$$ it reaches a height $$h$$. If one wishes to triple the maximum height then the ball be thrown with a velocity
  • $$\sqrt { 3 } { v }_{ 0 }$$
  • $$3{ v }_{ 0 }$$
  • $$9{ v }_{ 0 }$$
  • $$\dfrac{3}{2}{ v }_{ 0 }$$
Two balls $$A$$ and $$B$$ are simultaneously thrown. $$A$$ is thrown from the ground level with a velocity of $$20\ m{ s }^{ -1 }$$ in the upward direction and $$B$$ is thrown from a height of $$40\ m$$ in the downward direction with the same velocity. Where will the two balls meet?
  • $$15\ m$$
  • $$25\ m$$
  • $$35\ m$$
  • $$45\ m$$
A body moving in circular motion with constant speed has :
  • constant velocity
  • constant acceleration
  • constant kinetic energy
  • constant displacement
When the speed of a car is $$v$$, the minimum distance over which it can be stopped is $$s$$. If the speed becomes $$nv$$, what will be the minimum distance over which it can be stopped during the same time?
  • $$s/n$$
  • $$ns$$
  • $$s/ { n }^{ 2 }$$
  • $${ n }^{ 2 }s$$
The two ends of a train moving with constant acceleration pass a certain point with velocities $$u$$ and $$v$$. The velocity with which the middle point of the train passes the same point is
  • $${ \left( u+v \right) }/{ 2 }$$
  • $${ \left( { u }^{ 2 }+{ v }^{ 2 } \right) }/{ 2 }$$
  • $$\sqrt { { \left( { u }^{ 2 }+{ v }^{ 2 } \right) }/{ 2 } }$$
  • $$\sqrt { { u }^{ 2 }+{ v }^{ 2 } }$$
A stone is thrown upwards with a velocity $$v$$ from the top of a tower. It reaches the ground with a velocity $$3v$$. What is the height of the tower?
  • $$\dfrac{2v^2}{ g }$$
  • $$\dfrac{3v^2}{ g }$$
  • $$\dfrac{4v^2}{ g }$$
  • $$\dfrac{6v^2}{ g }$$
Two particles are projected vertically upwards with the same velocity on two different planets with accelerations due to gravities $${ g }_{ 1 }$$ and $${ g }_{ 2 }$$ respectively. If they fall back to their initial points of projection after lapse of times $${ t }_{ 1 }$$ and $${ t }_{ 2 }$$, respectively, then
  • $${ t }_{ 1 }{ t }_{ 2 }={ g }_{ 1 }{ g }_{ 2}$$
  • $${ t }_{ 1 }{ g }_{ 1 }={ t }_{ 2 }{ g }_{ 2 }$$
  • $${ t }_{ 1 }{ g }_{ 2 }={ t }_{ 2 }{ g }_{ 1}$$
  • $${ { t }_{ 1 } }^{ 2 }+{ { t }_{ 2 } }^{ 2 }={ g }_{ 1 }+{ g }_{ 2 }$$
A stone thrown vertically upwards with a speed of $$5{ m }/{ s }$$ attains a height $${ H }_{ 1 }$$. Another stone thrown upwards from the same point with a speed of $$10{ m }/{ s }$$ attains a height $${ H }_{ 2 }$$. The correct relation between $${ H }_{ 1 }$$ and $${ H }_{ 2 }$$ is
  • $${ H }_{ 2 }=4{ H }_{ 1 }$$
  • $${ H }_{ 2 }=3{ H }_{ 1 }$$
  • $${ H }_{ 1 }=2{ H }_{ 2 }$$
  • $${ H }_{ 1 }={ H }_{ 2 }$$
The displacement of a particle as a function of time is shown in figure. The figure indicates that
176716.png
  • the particle starts with a certain velocity, but the motion is retarded and finally the particle stops.
  • the velocity of the particle is constant throughout.
  • the acceleration of the particle is positive throughout.
  • the particle starts with a constant velocity, the motion is accelerated and finally the particle moves with another constant velocity.
The given figure shows the displacement-time curve of two particles $$P$$ and $$Q$$. Which of the following statements is correct?
176658_d560ffd1b4024680be5edb650f511dc6.png
  • Both $$P$$ and $$Q$$ move with uniform equal speed
  • $$P$$ is accelerated and $$Q$$ is retarded
  • Both $$P$$ and $$Q$$ move with uniform speeds but the speed of $$P$$ is more than the speed of $$Q$$
  • Both $$P$$ and $$Q$$ move with uniform speeds but the speed of $$Q$$ is more than the speed of $$P$$
Is the policeman right in arresting the driver to break speed limit?
  • Yes
  • No
  • Insufficient data to reply
  • The policeman demanded bribe
A ball released from a height falls $$5 m$$ in one second. In 4 seconds it falls through (Take $$g=10ms^{-2}$$):
  • $$20 m$$
  • $$1.25 m$$
  • $$40 m$$
  • $$80 m$$
A stone is thrown vertically upwards. When the particle is at one-half its maximum height, its speed is $$10  { m }/{ s }$$, then maximum height attained by particle is $$\left( g=10  { m }/{ { s }^{ 2 } } \right)$$:
  • $$8 m$$
  • $$10 m$$
  • $$15 m$$
  • $$20 m$$
A ball is dropped downwards, after $$1$$ sec another ball is dropped downwards from the same point. What is the distance between them after $$3$$ sec? (Take $$g=10ms^{-2}$$)
  • $$20m$$
  • $$25m$$
  • $$50m$$
  • $$9.8m$$
Two stones are thrown from the top of a tower, one straight down with an initial speed $$u$$ and the second straight up with the same speed $$u$$. When the two stones hit the ground, they will have speeds in the ratio
  • $$2:3$$
  • $$2:1$$
  • $$1:2$$
  • $$1:1$$
A body dropped from a height $$h$$ with an initial speed zero, strikes the ground with a velocity $$3\ { km }/{ h }$$. Another body of same mass dropped from the same height $$h$$ with an initial speed $$u=4\   { km }/{ h}$$. Find the final velocity of second mass, with which it strikes the ground.
  • $$3\ { km }/{ h }$$
  • $$4\ { km }/{ h }$$
  • $$5\ { km }/{ h }$$
  • $$6\ { km }/{ h }$$
Similar balls are thrown vertically each with a velocity $$20\ { m }/{ s }$$, one on the surface of earth and the other on the surface of moon. What will be ratio of the maximum heights attained by them? $$($$Acceleration on moon $$=\dfrac{g}{6}\ m / s^2$$ approximately, where $$g$$ is gravitational acceleration due to earth$$)$$
  • $$6$$
  • $$\displaystyle\dfrac { 1 }{ 6 }$$
  • $$\displaystyle\dfrac { 1 }{ 5 }$$
  • None of these
In uniform circular motion
  • both velocity and speed are constant
  • speed is constant but velocity changes
  • both speed and velocity change
  • velocity is constant but speed changes
0:0:1


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