CBSE Questions for Class 9 Physics Motion Quiz 13 - MCQExams.com

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)
  • $$0.45m{s}^{-2}$$
  • $$0.33m{s}^{-2}$$
  • $$0.30m{s}^{-2}$$
  • $$1m{s}^{-2}$$
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
  • $$24\ m$$
  • $$16\ m$$
  • $$8\ m$$
  • $$12\ m$$
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 $$(take\ g=10\ m/s^{2})$$
  • $$40\ m$$
  • $$45\ m$$
  • $$50\ m$$
  • $$60\ m$$
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:
  • $$1 : 3 : 5 ........$$
  • $$ 1^2 : 3^2 : 5^2 : ........... $$
  • $$ \left( 1-\sqrt { 2 } \right) :\left( \sqrt { 2 } \sqrt { 3 } \right) :\left( \sqrt { 3 } -\sqrt { 4 } \right) ....... $$
  • $$1 : 2 : 3 .......$$
 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 ?
  • $$\sqrt 2 {v_0}$$
  • $${v_0}$$
  • Zero
  • $$2 {v_0}$$
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?
  • $$2$$ m
  • $$4$$ m
  • $$6$$ m
  • $$8$$ 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
  • uniform speed and acceleration of constant magnitude
  • Non-uniform velocity and acceleration
  • uniform velocity and zero acceleration
  • 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 ($$g = 10m/{s}^{2}$$?)
  • $$10m/{s}^{2}$$
  • $$20m/{s}^{2}$$
  • $$30m/{s}^{2}$$
  • $$40m/{s}^{2}$$
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:
  • $$ { d }_{ 1 }:{ d }_{ 2 }:{ d }_{ 3 }=1:1:2$$
  • $$ { d }_{ 1 }:{ d }_{ 2 }:{ d }_{ 3 }=1:2:3$$
  • $$ { d }_{ 1 }:{ d }_{ 2 }:{ d }_{ 3 }=1:3:5$$
  • $$ { d }_{ 1 }:{ d }_{ 2 }:{ d }_{ 3 }=1:5:9$$
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 
  • $$\sqrt { 10 } m/{ s }^{ 2 }$$
  • $$\sqrt { 4 } m/{ s }^{ 2 }$$
  • $$\sqrt { 5 } m/{ s }^{ 2 }$$
  • $$\sqrt { 2 } m/{ s }^{ 2 }$$
Is it possible for an object's velocity to increase while its acceleration decreases?
  • No, this is impossible because of the way in which acceleration is defined.
  • No, because if acceleration is decreasing the object will be slowing down.
  • No, because velocity and acceleration must always be in the same direction.
  • 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 :-
  • zero
  • 250 m
  • 100 m
  • 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 
  • $$ \frac {u}{2T}(2T+1) $$
  • $$ \frac {u}{2T}(2T-1) $$
  • $$ \frac {u}{T}(2T+1) $$
  • $$ \frac {u}{T}(T-1) $$
Corresponding to the process shown in figure, what is heat given to the gas in the process ABCA ?
1371068_7e731664c3094b6a924a6489173d7001.png
  • 1 J
  • $$ \dfrac {3}{2} J $$
  • $$\dfrac{1}{2}$$J
  • 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
  • half as far
  • twice as far
  • four times as far
  • 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 
  • $$\sqrt { 10 }\ m/{ s }^{ 2 }$$
  • $$\sqrt { 4 }\ m/{ s }^{ 2 }$$
  • $$\sqrt { 5 }\ m/{ s }^{ 2 }$$
  • $$\sqrt { 2 }\ m/{ s }^{ 2 }$$
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 
  • $$\sqrt { 3 } : \sqrt { 2 } : 1$$
  • $$3 : 2 : 1$$
  • $$9 : 4 : 1$$
  • $$1 : ( \sqrt { 2 } - 1 ) : ( \sqrt { 3 } - \sqrt { 2 } )$$
What is the angle between instantaneous displacement and acceleration during the retarded motion

  • zero
  • $$

    \pi

    $$
  • $$

    \frac{\pi}{2}

    $$
  • $$

    \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$$  for the box to come to rest. Considering the height of the conveyer belt to be negligible, the distance moved by the box in the conveyor belt is:
  • $$0$$
  • $$0.2$$
  • $$0.4$$
  • $$0.8$$
In a damped oscillator, the mass of the oscillator is m = 200g, force constant is K = 90N/m and the damping constant b is 40 g/s. Find the time taken for its mecharical energy to drop to half its initial value 
  • 0.3s
  • 0.208 s
  • 6.93s
  • 3.46s
A body moving with constant acceleration covers 24 m in the $$4^{th}$$ second and 36 m in the $$6^{th}$$ second. The initial velocity of the body is 
  • $$12 ms^{-1}$$
  • $$3 ms^{-1}$$
  • $$4 ms^{-1}$$
  • $$5 ms^{-1}$$
In the distance-time graph of $$3$$ cars $$A, B$$  and $$C$$ which car has the highest speed and lowest speed.
1445166_32f37768a17b4fb1bbc00ac597f6e28d.png
  • $$A , C$$
  • $$C,A$$
  • $$A,B$$
  • $$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$$, then the initial acceleration of the block is  
  • $$15$$ $$m/s^2$$
  • $$10$$ $$m/s^2$$
  • $$2.5$$ $$m/s^2$$
  • $$5$$ $$m/s^2$$
A body of mass 5 kg having a velocity of 80 $$ms^{-1}$$  experiences a force in the opposite direction. The body is brought to rest in 8 sec. What is the retardation produced by the force? 
  • $$10ms^{-2}$$
  • $$15ms^{-2}$$
  • $$20ms^{-2}$$
  • $$25ms^{-2}$$
A body starting with initial velocity $$u$$ comes back to the starting point in $$t$$ seconds. Then the acceleration is
  • -2 u/t
  • 2 /t
  • t/2u
  • u/t
A car accelerates uniformly from $$18 km/h$$ to $$36 km/h$$ in $$5s$$.  The distance covered by the car will be 
  • $$1 m$$
  • $$18 m$$
  • $$37.5 m$$
  • none of theses
The acceleration time graph of a particle moving along a straight line is as shown in the figure. After what time the particle acquires $$0$$ velocity.

Note :- The particle initially starts at rest. 

1554653_7542a2df2ef646cc819fed0d86ccb1e6.png
  • $$12 \ s$$
  • $$8 \ s$$
  • $$5 \ s$$
  • $$16 \ s$$ 
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 
  • $$zero$$
  • $$40\sqrt { 2 } $$ km/h north-east
  • $$40\sqrt { 2 } $$ km/h south-east
  • $$None$$
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?
  • 1 : 1 : 1
  • 1 : 2 : 3
  • 1 :3 : 5
  • 1 : 5 : 9
The velocity-time plot for a particle moving on a straight line is shown in the figure, then?
1702857_473b24800f21493dbaebe959f2bda5cc.png
  • The particle has a constant acceleration
  • The particle has never turned around
  • 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
  • Both (a) and (c) are correct
Consider the above graph, which of the following correctly represents the final and initial velocity ($$v$$ and $$u$$) respectively?
1953088_bb22360352974b168918786f5dda6e18.png
  • $$OA$$, $$OC$$
  • $$OA$$, $$BD$$
  • $$BC$$, $$OA$$
  • $$OA$$, $$BC$$
Which of the following information is correct from the above graph?
1953090_a079ce933440409e8b0c7f367f98c012.PNG
  • $$BC = BD + DC$$
  • $$v = BD + DC$$
  • $$BD + OA$$
  • All of these
In the above graph, $$BC$$ is the ________ and $$OC$$ is the _______.
1953086_a5c815f48342496ea68f07bccae0c67c.PNG
  • Total time, final velocity
  • Final velocity, total time
  • Total time, inital velocity
  • Initial velocity, final velocity
In the above graph, the velocity of the body changes from $$A$$ to $$B$$ in a time $$t$$ at a _______ rate.
1953085_0fb1c09426664ea68383bc12ab686872.PNG
  • Uniform
  • Non-uniform
  • Zig-zag
  • None of these
Rectilinear motion can be uniform but circular motion can't
  • True
  • False
0:0:1


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