MCQ Questions for Class 9 Physics Motion Quiz 13

When a block of mass $$3\ kg$$ is pushed by three persons from the left to the right, a constant acceleration of $$0.2m{s}^{-2}$$ is produced in the block. If five persons push the block in the same direction together, then the magnitude of the acceleration of the block will be: (Assume that each person applies equal force)

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$$0.45m{s}^{-2}$$
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$$0.33m{s}^{-2}$$
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$$0.30m{s}^{-2}$$
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$$1m{s}^{-2}$$

A particle starts from the origin at $$t=0s$$ with a velocity of $$10.0j\ m/s$$ and moves in the $$xy-$$plane with a constant acceleration of the $$(8\hat {i}+2j)ms^{-2}$$. Then $$y-$$coordinate of the particle in $$2\ sec$$ is

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$$24\ m$$
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$$16\ m$$
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$$8\ m$$
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$$12\ m$$

A balloon is rising vertically up at constant speed $$10\ m/s$$. A stone is dropped from it when the balloon is at a height of $$40\ m$$. Total distance covered by the stone before reaching the ground is $$(take\ g=10\ m/s^{2})$$

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$$40\ m$$
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$$45\ m$$
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$$50\ m$$
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$$60\ m$$

A particle starts from rest with constant acceleration. The ratio of speed attained by a particle at $$t = 1\ s,\ 2\ s,\ 3\ s.........$$ will be:

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$$1 : 3 : 5 ........$$
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$$ 1^2 : 3^2 : 5^2 : ........... $$
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$$ \left( 1-\sqrt { 2 } \right) :\left( \sqrt { 2 } \sqrt { 3 } \right) :\left( \sqrt { 3 } -\sqrt { 4 } \right) ....... $$
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$$1 : 2 : 3 .......$$

A particle is moving on a circular path of radius R with constant speed $$v_0$$. What is the change in magnitude of velocity when it completes $$\frac{{{3^{th}}}}{4}$$ of the complete circular path ?

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$$\sqrt 2 {v_0}$$
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$${v_0}$$
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Zero
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$$2 {v_0}$$

A water drop falls at regular intervals from a tap $$9$$ m above the ground. The fourth drop is leaving the tap at the instant, the first drop touches the ground. How high is the third drop at that instant?

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$$2$$ m
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$$4$$ m
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$$6$$ m
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$$8$$ m

A car is moving on a circular track of radius R covering equal distance in equal intervals of time. This shows that the car has

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uniform speed and acceleration of constant magnitude
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Non-uniform velocity and acceleration
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uniform velocity and zero acceleration
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Both (1) and (2)

A rocket of initial mass $$5000 kg$$ ejects gets at a constant rate of $$60kg/s$$ with a relative speed of $$2050 m/s$$. Acceleration of the rocket 15 second after it is blasted off from the surface of earth will be ($$g = 10m/{s}^{2}$$?)

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$$10m/{s}^{2}$$
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$$20m/{s}^{2}$$
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$$30m/{s}^{2}$$
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$$40m/{s}^{2}$$

A particle experienced a constant acceleration for $$6$$ seconds after starting from rest. If it travels a distance $$ { d }_{ 1 }$$ in the first two seconds, $$ { d }_{ 2 }$$ in the next $$2$$ seconds, and a distance $$ { d }_{ 3 }$$ in the last $$2$$ seconds, then:

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$$ { d }_{ 1 }:{ d }_{ 2 }:{ d }_{ 3 }=1:1:2$$
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$$ { d }_{ 1 }:{ d }_{ 2 }:{ d }_{ 3 }=1:2:3$$
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$$ { d }_{ 1 }:{ d }_{ 2 }:{ d }_{ 3 }=1:3:5$$
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$$ { d }_{ 1 }:{ d }_{ 2 }:{ d }_{ 3 }=1:5:9$$

A particle is moving in x-y plane . At certain instant of time. The components of its velocity and acceleration are as follows $$V_x = 3\ m/s$$, $$V_y = 4\ m/s$$, $${ a }_{ x }=2\ m/s^{ 2 }$$ and $${ a }_{ y }=1\ m/s^{ 2 }$$. The rate of change of speed at this moment is

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$$\sqrt { 10 } m/{ s }^{ 2 }$$
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$$\sqrt { 4 } m/{ s }^{ 2 }$$
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$$\sqrt { 5 } m/{ s }^{ 2 }$$
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$$\sqrt { 2 } m/{ s }^{ 2 }$$

Is it possible for an object's velocity to increase while its acceleration decreases?

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No, this is impossible because of the way in which acceleration is defined.
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No, because if acceleration is decreasing the object will be slowing down.
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No, because velocity and acceleration must always be in the same direction.
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Yes, an example would be a falling object in a viscous medium, where the acceleration continuously decreases but velocity increases until a certain point.

The position-time $$(x - t)$$ graph for a body thrown vertically upwards from ground is best shown by

In a motion with constant acceleration the velocity is reduced to zero in $$5$$ seconds and after covering a distance of $$100\ m$$. The distance covered by the particle in next $$5$$ second will be :-

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zero
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250 m
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100 m
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500 m

A particle starts from rest with uniform acceleration and its velocity after T seconds is $$u$$. The displacement of the particle in last second of this motion is

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$$ \frac {u}{2T}(2T+1) $$
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$$ \frac {u}{2T}(2T-1) $$
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$$ \frac {u}{T}(2T+1) $$
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$$ \frac {u}{T}(T-1) $$

Corresponding to the process shown in figure, what is heat given to the gas in the process ABCA ?

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1 J
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$$ \dfrac {3}{2} J $$
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$$\dfrac{1}{2}$$J
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0

Starting from rest objects $$1$$ falls freely for $$4$$ seconds and object $$2$$ falls freely for $$8$$ seconds .Compared to object $$1$$, object $$2$$ falls

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half as far
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twice as far
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four times as far
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sixteen times as far

A particle is moving in x-y plane . At certain instant of time. The components of its velocity and acceleration are as follows $$V_x=3\ m/s$$, $$V_y = 4\ m/s$$, $${ a }_{ x }=2\ m/s^{ 2 }$$ and $${ a }_{ y }=1\ m/s^{ 2 }$$ The rate of change of speed at this moment is

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$$\sqrt { 10 }\ m/{ s }^{ 2 }$$
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$$\sqrt { 4 }\ m/{ s }^{ 2 }$$
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$$\sqrt { 5 }\ m/{ s }^{ 2 }$$
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$$\sqrt { 2 }\ m/{ s }^{ 2 }$$

A particle is released from rest from a tower of height $$3h$$ The ratio of time taken to fall equal heights $$h , t _ { 1 } : t _ { 2 } : t _ { 3 }$$ is

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$$\sqrt { 3 } : \sqrt { 2 } : 1$$
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$$3 : 2 : 1$$
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$$9 : 4 : 1$$
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$$1 : ( \sqrt { 2 } - 1 ) : ( \sqrt { 3 } - \sqrt { 2 } )$$

What is the angle between instantaneous displacement and acceleration during the retarded motion

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zero
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$$

\pi

$$
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$$

\frac{\pi}{2}

$$
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$$

\frac{\pi}{4}

$$

A conveyor belt is moving horizontally at a speed of $$4 \ m/sec$$ with a box of mass $$20 \ kg$$ on it. The box suddenly drops off the conveyer belt to the ground and it takes $$0.1 \ second$$ for the box to come to rest. Considering the height of the conveyer belt to be negligible, the distance moved by the box in the conveyor belt is:

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$$0$$
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$$0.2$$
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$$0.4$$
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$$0.8$$

In a damped oscillator, the mass of the oscillator is m = 200g, force constant is K = 90N/m and the damping constant b is 40 g/s. Find the time taken for its mecharical energy to drop to half its initial value

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0.3s
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0.208 s
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6.93s
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3.46s

A body moving with constant acceleration covers 24 m in the $$4^{th}$$ second and 36 m in the $$6^{th}$$ second. The initial velocity of the body is

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$$12 ms^{-1}$$
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$$3 ms^{-1}$$
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$$4 ms^{-1}$$
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$$5 ms^{-1}$$

In the distance-time graph of $$3$$ cars $$A, B$$ and $$C$$ which car has the highest speed and lowest speed.

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$$A , C$$
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$$C,A$$
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$$A,B$$
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$$B,A$$

A block of weight $$4 kg$$ is resting on a smooth horizontal plane. If it is struck by a jet of water at the rate of $$2 kg/s$$ and at the speed of $$10 m/s$$, then the initial acceleration of the block is

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$$15$$ $$m/s^2$$
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$$10$$ $$m/s^2$$
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$$2.5$$ $$m/s^2$$
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$$5$$ $$m/s^2$$

A body of mass 5 kg having a velocity of 80 $$ms^{-1}$$ experiences a force in the opposite direction. The body is brought to rest in 8 sec. What is the retardation produced by the force?

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$$10ms^{-2}$$
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$$15ms^{-2}$$
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$$20ms^{-2}$$
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$$25ms^{-2}$$

A body starting with initial velocity $$u$$ comes back to the starting point in $$t$$ seconds. Then the acceleration is

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-2 u/t
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2 /t
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t/2u
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u/t

A car accelerates uniformly from $$18 km/h$$ to $$36 km/h$$ in $$5s$$. The distance covered by the car will be

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$$1 m$$
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$$18 m$$
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$$37.5 m$$
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none of theses

The acceleration time graph of a particle moving along a straight line is as shown in the figure. After what time the particle acquires $$0$$ velocity.

Note :- The particle initially starts at rest.

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$$12 \ s$$
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$$8 \ s$$
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$$5 \ s$$
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$$16 \ s$$

A ship moves at 40 km/h due north and suddenly moves towards east through $$9\mathring { 0 } $$ and continuous to move with the same speed. Then the change in its velocity is

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$$zero$$
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$$40\sqrt { 2 } $$ km/h north-east
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$$40\sqrt { 2 } $$ km/h south-east
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$$None$$

A particle moves with constant acceleration for 6 seconds after starting from rest. The distance travelled during the first three consecutive 1 seconds interval is in the ratio?

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1 : 1 : 1
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1 : 2 : 3
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1 :3 : 5
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1 : 5 : 9

The velocity-time plot for a particle moving on a straight line is shown in the figure, then?

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The particle has a constant acceleration
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The particle has never turned around
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The average speed in the interval $$0$$ to $$10$$ s in the same as the average speed in the interval $$10$$ s to $$20$$ s
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Both (a) and (c) are correct