CBSE Questions for Class 9 Physics Motion Quiz 4 - MCQExams.com

A ball is thrown vertically upwards with a speed of $$10\ ms^{-1}$$ from the ground at the bottom of a tower $$200$$ $$m$$ high. Another is dropped vertically downward simultaneously, from the top of a tower. If $$g=10\ ms^{-2}$$ the time interval after which the projected body will be at the same level as the dropped body is:
  • $$20\ s$$
  • $$25\ s$$
  • $$2\sqrt{10}\;s$$
  • $$5\ s$$
A stone is dropped from the top of a tower of height $$49$$ $$m$$. Another stone is thrown up vertically with velocity of $$24.5\ m/s$$ from the foot of the tower at the same instant. They will meet in a time of
  • 1 s
  • 2 s
  • 0.5 s
  • 0.25 s
Two balls A and B are thrown simultaneously. A vertically upwards at a speed of $$15$$ m/s from the ground and B, vertically downwards from a height of $$30$$ m at the same speed along the same line of motion. They meet after a time of: 
  • 1 s
  • 2 s
  • 3 s
  • 4 s
A body is projected vertically upwards with a velocity $$u$$. It crosses a point in its journey at a height $$h$$ meter twice, just after $$1$$ and $$7 $$ seconds .The value of $$u$$ in $$ms^{-1}$$ is $$ (g= 10ms^{-2})$$
  • $$50$$
  • $$40$$
  • $$30$$
  • $$20$$
An object may have 
  • varying speed without having varying velocity
  • varying velocity without having varying speed
  • non zero acceleration without having varying velocity
  • non zero acceleration without having varying speed
The displacement ($$x$$) versus time ($$t$$) curve for two particles is as shown in figure. Which of the following statements is correct for time interval between $$0$$ to $$10$$ s?

2672.png
  • The particle $$A$$ is speeding up while $$B$$ is slowing down.
  • Both the particles are initially speeding up and then slowing down.
  • Both the particles are initially slowing down and then speeding up.
  • Particle $$A$$ is speeding up first and then slowing down while $$B$$ is slowing down first and then speeding up.
A stone is thrown vertically up from the ground. It reaches a maximum height of 50 m in 10 s. After what time will it reach the ground from the maximum height?
  • 5 s
  • 10 s
  • 20 s
  • 25 s
A body moving with uniform acceleration in a straight line is at points A, B, C, D after successive equal intervals of time. The distance AD is equal to:
  • BC
  • 2(BC)
  • 3(BC)
  • 4(BC)
A ball is released from the top of a tower of height $$h\ m$$. It takes $$T$$ seconds to reach the ground. What is the position of the ball in $$\dfrac{T}{3}$$ second?
  • $$\dfrac{h}{9}$$ metres from the ground
  • $$\dfrac{7h}{9}$$ metres from the ground
  • $$\dfrac{8h}{9}$$ metres from the ground
  • $$\dfrac{17h}{18}$$ metres from the ground
Two bodies, A(of mass 1kg) and B(of mass 3kg),are dropped from heights of 16 m and 25 m respectively. The ratio of the time taken by them to reach the ground is:-
  • $$\dfrac{5} {4}$$
  • $$\dfrac{12} {5}$$
  • $$\dfrac{5} {12}$$
  • $$\dfrac{4} {5}$$
A particle starts with a velocity $$200\ cm/s$$ and moves in a straight line with a retardation of $$10\ cm/s^{2}$$. Its displacement will be $$1500\ cm$$:
  • Only once at $$30\ s$$ from start
  • Only once at $$10\ s$$
  • Twice at $$10\ s$$ and $$30\ s$$
  • Always
The displacement-time graph of motion of a particle is shown in the figure. The ratio of the magnitudes of the speeds during the first two seconds and the next four seconds is:

2687.jpg
  • $$1:1$$
  • $$1:2$$
  • $$2:1$$
  • $$1:\sqrt{2}$$
A wooden block of mass $$10$$ gm is dropped from the top of a cliff $$100$$ m high. Simultaneously a bullet of mass $$10$$ gm is fired from the foot of the cliff  upward with a velocity $$100$$ m/s. The bullet and the wooden block will meet each other after a time of:
  • 10 s
  • 0.5 s
  • 1 s
  • 7 s
A ball is released from the top of a tower of height $$h$$ m. It takes $$T$$ s to reach the ground. What is the position of the ball in $$\dfrac{T}{3}$$ s?
  • $$\dfrac{h}{9}$$ m from the ground
  • $$\dfrac{7h}{9}$$ m from the ground
  • $$\dfrac{8h}{9}$$ m from the ground
  • $$\dfrac{17h}{18}$$ m from the ground
Suppose a boy is enjoying a ride on a merry-go-round which is moving with a constant speed of $$10\ ms^{-1}$$. It implies that the boy is :
  • at rest
  • moving with no acceleration
  • in accelerated motion
  • moving with uniform velocity

A ball is thrown upwards. It takes 4 s to reach back to the ground. Find its initial velocity.
  • $$30 ms^{-1}$$
  • $$10 ms^{-1}$$
  • $$40 ms^{-1}$$
  • $$20 ms^{-1}$$

A boy standing at the top of a tower of 20 $$m$$ height drops a stone. Assuming $$g=10 ms^{-2}$$, the velocity with which it hits the ground is:
  • $$20 ms^{-1}$$
  • $$40 ms^{-1}$$
  • $$5 ms^{-1}$$
  • $$10 ms^{-1}$$
A body is thrown vertically upwards with a velocity $$u$$, the greatest height $$h$$ to which it will rise is:
  • $$u/g$$
  • $$u^{2}/2g$$
  • $$u^{2}/g$$
  • $$u/2g$$

The velocity of a bullet is reduced from $$100 \ m/s$$ to $$0 \ m/s$$ while travelling through a wooden block of thickness $$10\  cm$$. The retardation, assuming it to be uniform will be:
  • $$5 \times {10^4}\ m/{s^2}$$
  • $$12 \times {10^4}\ m/{s^2}$$
  • $$14 \times {10^4}\ m/{s^2}$$
  • $$1 \times {10^4}\ m/{s^2}$$
Two objects of masses $$m_{1}$$ and $$m_{2}$$ having the same size are dropped simultaneously from heights $$h_{1}$$ and $$h_{2}$$ respectively. Find out the ratio of time they would take in reaching the ground.
  • $$\sqrt{\dfrac{h_{1}}{h_{2}}}.$$
  • $$\sqrt{\dfrac{h_{2}}{h_{1}}}.$$
  • $${\dfrac{h_{1}}{h_{2}}}.$$
  • $${\dfrac{h_{2}}{h_{1}}}.$$
A particle is moving in a circular path of radius $$r$$. The magnitude of displacement after half a circle would be :
  • Zero
  • $$\pi r$$ 
  • $$2 r$$
  • $$2 \pi r$$ 

A ball is dropped from height $$h$$ and another from $$2h$$. The ratio of time taken by the two balls to reach ground is:
  • $$1:\sqrt{2}$$
  • $$\sqrt{2}:1$$
  • $$2:1$$
  • $$1:2$$
A particle starts its motion from rest under the action of a constant force. If the distance covered in first 10 seconds is $$S_1$$ and that covered in the first 20 seconds is $$S_2$$ then:
  • $$S_2$$ = $$S_1$$
  • $$S_2$$ = $$2S_1$$
  • $$S_2$$ = $$3S_1$$
  • $$S_2$$ = $$4S_1$$

If a body is thrown up with the velocity of $$15 m/s$$, then maximum height attained by the body is $$(g=10 \ m/s^2)$$
  • $$11.25 m$$
  • $$16.2 m$$
  • $$24.5 m$$
  • $$7.62 m$$
An electron starting from rest has a velocity that increases linearly with time,i.e. v=kt where $$k=2\ m/s^2$$. The distance covered in the first three seconds will be
  • 36m
  • 27m
  • 18m
  • 9m
The velocity of a body at any instant is 10 m/s. After 5 sec, velocity of the particle is 20 m/s. The velocity at 3 seconds before is
(assume uniform accelaration)
  • 8 m/sec
  • 4 m/sec
  • 6 m/sec
  • 7 m/sec

In the velocity-time graph, AB shows that the body has
95921_07f4d44822af41a582688de53e27cf4a.png
  • uniform acceleration
  • non-uniform retardation
  • uniform speed
  • initial velocity OA and is moving with uniform retardation

In the graph provided, the velocity
96028_262b10064fa043bc8f46d1fca46636e5.png
  • increases between point 0 and A
  • increases between point A and B
  • decreases between points A and B
  • is zero throughout
$$N/kg$$ is the unit of :
  • Retardation
  • Acceleration
  • Rate of change of velocity
  • All of these
A girl walks along a straight path to drop a letter in the letterbox and
comes back to her initial position. Her displacement-time graph is shown in the figure. Find the average velocity.

78412_36bbb430c5664bb181623e636ae63917.png
  • 1 m/s
  • 2 m/s
  • -2 m/s
  • 0 m/s
The rate of change of displacement with time is
  • speed
  • acceleration
  • retardation
  • velocity
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
  • $$\theta=60^0 \:in \:N - E \:direction$$
  • $$\theta=30^0 \:in \:N - E \:direction$$
  • $$\theta=60^0 \:in \:S - W \:direction$$
  • $$\theta=30^0 \:in \:S - W \:direction$$
A particle is moving in a circular path of radius r. Its displacement after moving through half the circle would be :
  • Zero
  • $$r$$
  • $$2r$$
  • $$\dfrac{2}{r}$$
Two balls are dropped from height $$h_1$$ and $$h_2$$ respectively. What is the ratio of their velocities on reaching the ground is?
  • $$\sqrt{\dfrac{h_2}{h_1}}$$
  • $$\sqrt{\dfrac{h_1}{h_2}}$$
  • $$\dfrac{h_2}{h_1}$$
  • $$\dfrac{h_1}{h_2}$$
A body starting from rest in travelling with an acceleration of $$6m/s^2$$. Find the distance traveled by it in $$6^{th}$$ second.
  • $$36$$ mts
  • $$28$$ mts
  • $$54$$ mts
  • $$33$$ mts
From kinematics, correct equation of motion for $$S$$ is/are :
  • $$S=ut-\frac {1}{2}at^2$$
  • $$S=ut+\frac {1}{2}at^2$$
  • Both (a) and (b)
  • None of these
Speed of a body depends on 
  • Time 
  • Mass of the body 
  • Distance travelled by the body 
  • Both A and C
A particle is projected up with a velocity of  $$\sqrt{29}\ ms^{-1}$$ from a tower of height 10m. Its velocity on reaching the ground is    $$ x $$ $$\ ms^{-1}$$. Find $$ x $$.
  • 5
  • 10
  • 15
  • 20
Average speed of a body is
  • Total Distance $$\div $$ Total Time
  • Total Distance + Total Time
  • Both (a) and (b)
  • None of these
If a body is thrown up with an initial velocity u and covers a maximum height of h, then h is equal to
  • $$\dfrac{u^2}{2g}$$
  • $$\dfrac{u}{2g}$$
  • $$2u^2g$$
  • None of these
A stone is projected up with a velocity of $$4.9\ m/s$$ from the top of a tower and it reaches the ground after 3 s. Then the height of that tower is
  • 4.9 m
  • 19.6 m
  • 9.8 m
  • 29.4 m
If an object is thrown vertically up with a velocity of $$19.6\ ms^{-1}$$, it strikes the ground after $$x$$ second, find $$x$$. 
  • 1
  • 2
  • 4
  • 8
The relationship between average speed, time and distance is
  • Average speed = distance $$\times $$ time
  • Average speed $$= \cfrac{\text{total distance}}{\text{total time}}$$
  • $$\text{Time} = \cfrac{\text{average speed}}{\text{distance}}$$
  • $$\text{Distance} = \text{average speed } \times \text{time}$$
A freely falling body from rest acquires velocity V falling through a distance h. After the body falls through a further distance h velocity acquired by it is
  • 2v
  • v
  • $$\sqrt{2}$$v
  • 4v
An object is thrown vertically upward with a velocity of $$10\ ms^{-1}$$. It strikes the  ground after _______ seconds. (Take $$g  = 10\ ms^{-2}$$)
  • 10
  • 2
  • 5
  • 1
A stone is dropped from a rising balloon at a height of 300 m above the ground and it reaches the ground in 10 s. The velocity of the balloon when it was dropped is :
  • $$19 m s^{-1}$$
  • $$19.6 m s^{-1}$$
  • $$29 m s^{-1}$$
  • $$0 m s^{-1}$$
An object is released from a balloon rising up with a constant speed of $$2\ ms^{-1}$$. Its magnitude of velocity after $$1\ s$$ in $$\ ms^{-1}$$ is
  • 5.3
  • 7.8
  • 2.8
  • 6.4
When a body is projected vertically up from the ground its velocity is reduced to $$\frac{1}{4}$$th of its velocity at ground at height $$h$$. Then the maximum height reached by the body is
  • $$\dfrac{15}{32}h$$
  • $$\dfrac{15}{16}h$$
  • $$\dfrac{15}{8}h$$
  • $$\dfrac{5}{4}h$$
A car travels with a uniform velocity of $$25\, m\, s^{-1}$$ for 5 s. The brakes are then applied and the car is uniformly retarded and comes to rest in further 10 s. Find the acceleration.
  • $$5\, m\, s^{-2}$$
  • $$-2.5\, m\, s^{-2}$$
  • $$25\, m\, s^{-2}$$
  • $$10\, m\, s^{-2}$$
A body projected vertically up with a velocity of 10 m s$$^{-1}$$ reaches a height of 20 m. If it is projected with a velocity of 20 m s$$^{-1}$$, then the maximum height reached by the body is :
  • 20 m
  • 10 m
  • 80 m
  • 40 m
0:0:1


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