CBSE Questions for Class 11 Engineering Physics Motion In A Plane Quiz 5 - MCQExams.com

A wheel rotates with the constant acceleration of $$2.0\ rad/s^2 $$, if the wheel starts from rest the  number of revolution it makes in first ten seconds will be approximately 
  • 32
  • 24
  • 16
  • 8
If $$\overrightarrow{C}=\overrightarrow{A}+\overrightarrow{B},$$ then
  • $$|\overrightarrow{C}| $$ is always greater than $$|\overrightarrow{A}| $$
  • It is possible to have $$|\overrightarrow{C}| < |\overrightarrow{A}| $$ and $$|\overrightarrow{C}|<|\overrightarrow{B}| $$
  • $$|\overrightarrow{C}| $$ is always equal to $$|\overrightarrow{A}|+|\overrightarrow{B}| $$
  • $$|\overrightarrow{C}| $$ is never equal to $$|\overrightarrow{A}+\overrightarrow{B}| $$
Which one of the following is not the vector quantity?
  • Torque
  • Displacement
  • Velocity
  • Speed
Match column I with column II and select the correct answer using the codes given below:
       Column I                                       Column II
(A)  F = constant$$\neq $$0          (p)  Directional change
(B)  F = 0                            (q)  Variable acceleration
(C)  F$$\neq $$ constant               (r)  No change in momentum
(D)  F$$\neq $$ 0                           (s)  If a body moves uniformly along a circle
  • A - (p); B - (s); C - (q); D - (r)
  • A - (q); B - (p); C - (r); D - (s)
  • A - (p); B - (r); C - (q); D - (s)
  • A - (s); B - (q); C - (p); D - (r)
Which one of the following is a scalar quantity?
  • Displacement
  • Electric field
  • Acceleration
  • Work
The following table represents the velocity of a moving body at different  instants of  time.
Times (s)051015202530
Velocity $$(m\,s^{-1})$$1015202030150
The velocity-time graph is as shown in figure. For which interval of time the body has a uniform motion ? Find the velocity in this time interval ?
204500.png
  • from t = 0 s to t = 5 s; 10 m/s
  • from t = 5 s to t = 10 s; 20 m/s
  • from t = 10 s to t = 15 s; 20 m/s
  • from t = 15 s to t = 25 s; 30 m/s
Which one is a vector quantity?
  • Time
  • Temperature
  • Flux density
  • Magnetic field intensity
A disc is rotating in a room. A boy standing near the rim of the disc of radius $$R$$ finds the water droplet falling from the ceiling is always falling on his head. As one drop hits his head, other one starts from the ceiling. If height of the roof above his head is $$H$$, then angular velocity of the disc is
  • $$\displaystyle \pi \sqrt{\frac{2g R}{H^{2}}}$$
  • $$\displaystyle \pi \sqrt{\frac{2g H}{R^{2}}}$$
  • $$\displaystyle \pi \sqrt{\frac{2g}{H}}$$
  • None of these
A point moves along a circle having a radius $$20 cm$$ with a constant tangential acceleration $$5 cm$$ $$\displaystyle s^{-2}.$$ How much time is needed after motion begins for the normal acceleration of the point to be equal to tangential acceleration?
  • 1 s
  • 2 s
  • 3 s
  • 4 s
Three particles A, B and C move in a circle in anticlockwise direction with speeds 1 $$\displaystyle ms^{-1}, 2.5 ms^{-1}\:and\:2 ms^{-1}$$ respectively. The initial positions of A, B and C are as shown in figure. The ratio of distance travelled by B and C by the instant A, B and C meet for the first time is

240815_c2d0e5678c144436bac119a3de316c5d.png
  • 3:2
  • 5:4
  • 3:5
  • data insufficient
A shaft initially rotating at $$1725$$ rpm is brought to rest uniformly in $$20s.$$ The number of revolutions that the shaft will make during this time is
  • $$1680$$
  • $$575$$
  • $$287$$
  • $$627$$
Which of the following quantities is not a vector?
  • Mass
  • Displacement
  • Weight
  • Acceleration
A particle rotates in a circular path of radius $$54 m$$ with varying speed $$\displaystyle v= 4t^{2}.$$ Here $$v$$ is in m/s and $$t$$ in second. Find angle between velocity and acceleration at $$t=3 s$$.
  • $$\displaystyle 45^{\circ}$$
  • $$\displaystyle 75^{\circ}$$
  • $$\displaystyle 90^{\circ}$$
  • $$\displaystyle 15^{\circ}$$
In a golf tournament, if we designate the hole as the origin, and the putter (like a bat) is at -5.0 m at time 0 s, the velocity-time graph for the golf ball will be

245806.png
  • a straight line inclined to the time axis
  • a straight line parallel to the time axis
  • a concave curve
  • a convex curve
What is the change in velocity in the question?
  • $$\displaystyle u\sin \alpha $$ (downwards)
  • $$\displaystyle u\cos \alpha $$ (downwards)
  • $$\displaystyle 2u\sin \alpha $$ (downwards)
  • $$\displaystyle 2u\cos \alpha $$ (downwards)
A particle is projected from horizontal making an angle $$\displaystyle 60^{\circ}$$ with initial velocity $$40\ ms^{-1}$$. Find the time taken by the particle to make angle $$\displaystyle 45^{\circ}$$ from horizontal.
  • $$1.5\ s$$
  • $$2.5\ s$$
  • $$3.5\ s$$
  • $$4.5\ s$$
Following sets of three forces act on a body. Whose resultant cannot be zero?
  • $$\;10,10,10$$
  • $$\;10,10,20$$
  • $$\;10,20,20$$
  • $$\;10,20,40$$
The distance between the point $$P(x,y,z)$$ and plane $$xz$$ is :
  • $$x$$
  • $$y$$
  • $$z$$
  • $$xy$$
$$A, B, C$$ are fixed points and $$P$$ is a variable point such that the resultant of forces at $$P$$ represented by $$\displaystyle \vec{PA}$$ and $$\displaystyle \vec{PB}$$ always passes through $$C$$ and $$D$$ is the mid-point of $$AB$$, then locus of $$P$$ is
  • circle passing through $$A, B, C$$ and $$D$$
  • straight line passing through $$C$$ and $$D$$
  • straight line passing through $$A$$ and $$B$$
  • none of these
On a bright sunny day, a boy standing on a sea shore is flying a kite. In what direction will his kite fly ?
  • Towards the sea
  • upward the sea 
  • downward the sea
  • none of these 
Figure shows three vectors $$\vec{a},\vec{b}$$ and $$\vec{c}$$, where $$R$$ is the midpoint of $$PQ$$. Then which of the following relations is correct?
272943_7c9815020d1a496a89c739dc2df0958e.png
  • $$\;\vec{a}+\vec{b}=2\vec{c}$$
  • $$\;\vec{a}+\vec{b}=\vec{c}$$
  • $$\;\vec{a}-\vec{b}=2\vec{c}$$
  • $$\;\vec{a}-\vec{b}=\vec{c}$$
How many minimum number of coplanar vectors which represent same physical quantity having different magnitudes can be added to give zero resultant.
  • (A)$$\;2$$
  • (B)$$\;3$$
  • (C)$$\;4$$
  • (D)$$\;5$$
A physical quantity which has a direction:-
  • must be a vector
  • may be a vector
  • must be a scalar
  • must be zero. 
If $$\vec{a}$$ is a vector and $$x$$ is a non-zero scalar, then
  • $$\;x\vec{a}$$ is a vector in the direction perpendicular to $$\vec{a}$$
  • $$\;x\vec{a}$$ is a vector collinear to $$\vec{a}$$
  • $$\;x\vec{a}$$ and $$\vec{a}$$ have independent directions
  • $$x\vec a $$ is a scalar
If $$\displaystyle \vec{a},\vec{b},\vec{c},\vec{d},\vec{e},\vec{f}$$ are position vectors of 6 points A, B, C, D, E & F respectively such that $$\displaystyle 3\vec{a}+4\vec{b}=6\vec{c}+\vec{d}=4\vec{e}+3\vec{f}=\vec{x}$$ then
  • $$\displaystyle \overline{AB}$$ is parallel to $$\displaystyle \overline{CD}$$
  • line AB, CD and EF are concurrent
  • $$\displaystyle \frac{\vec{x}}{7}$$ is position vector of the point dividing CD in ratio 1 : 6
  • A, B, C, D, E & F are coplanar
When a ceilling fan is switched off its angular velocity reduces to $$50\%$$ while it makes $$36$$ rotations. How many more rotation will it make before coming to rest (Assume uniform angular retardation):
  • $$\;18$$
  • $$\;12$$
  • $$\;36$$
  • $$\;48$$
Two bullets are fired simultaneously, horizontally and with different speeds from the same place. Which bullet will hit the ground first-
  • The faster one
  • The slower one
  • Both will reach simultaneously
  • Depends on the masses
An object is projected with a velocity of $$20 m/s$$ making an angle of $$45$$ with horizontal. The equation for the trajectory is $$h = Ax - Bx^{2}$$, where $$h$$ is height, $$x$$ is horizontal distance, $$A$$ and $$B$$ are constants. The ratio $$A : B$$ is- $$($$$$g = 10 m/s^{2}$$$$)$$
  • $$1 : 5$$
  • $$5 : 1$$
  • $$1 : 40$$
  • $$40 : 1$$
Which of the following is scalar ?
  • Current
  • Velocity
  • Force
  • Acceleration
An athlete completes half a round of a circular track of radius, $$R$$. Then, the displacement and distance covered by the athlete are 
  • $$2R\;and\;\pi R$$
  • $$\pi R\;and\;2 R$$
  • $$R\;and\;2\pi R$$
  • $$2\pi R\;and\;R$$
Which of the following pairs of quantities have same dimensional formula of which one is a vector and other is scalar ?
  • Work and energy
  • Torque and work
  • Impulse and momentum
  • Power and pressure
An athlete completes one round of a circular track of radius $$R$$ in $$40$$ seconds. What will be his displacement at the end of $$2$$ minute $$20$$ seconds?
  • $$0$$
  • $$2R$$
  • $$2\pi R$$
  • $$7\pi R$$
Position vector of a particle is given by $$\vec{r}=a cos\omega t\hat {i}+a sin\omega t\hat {j}$$. Which of the following is/are true?
  • velocity vector is parallel to position vector
  • velocity vector is perpendicular to position vector
  • acceleration vector is directed towards the origin
  • acceleration vector is directed away from the origin
Forces proportional to $$AB,BC$$ and $$2CA$$ act along the sides of triangle $$ABC$$ in order. Their resultant represented in magnitude and direction as
  • $$\;\overrightarrow{CA}$$
  • $$\;\overrightarrow{AC}$$
  • $$\;\overrightarrow{BC}$$
  • $$\;\overrightarrow{CB}$$
A car runs at constant speed on a circular track of radius 100 m taking 62.8 s on each lap. What is the average speed and average velocity on each complete lap? $$(\pi\, =\, 3.14)$$
  • Velocity 10 m/s, speed 10 m/s
  • Velocity zero, speed 10 m/s
  • Velocity zero, speed zero
  • Velocity 10 m/s, speed zero
A ball is thrown upwards. It returns to ground describing a parabolic path.Which of the following remains constant. 
  • Speed of the ball
  • Kinetic energy of the ball
  • Vertical component of velocity
  • Horizontal component of velocity.
A body is projected with a velocity of $$98\;ms^{-1}$$. If acceleration due to gravity be $$9.8\;m/s^{2}$$, then:-
  • It will go upto the maximum height of $$980 m$$, after $$10second$$
  • It will go upto the height of $$490 m$$, is $$5 second$$
  • It will come back to earth in $$10 seconds$$
  • Its speed reduced to $$49\;ms^{-1}$$ after $$5 second$$
Vector sum of two forces of 10N and 6N cannot be :-
  • 4N
  • 8N
  • 12N
  • 2N
Figure shows the three vectors $$ \overrightarrow a , \overrightarrow b $$ and $$ \overrightarrow c $$ , where R is the midpoint of PQ. Then which of the following relations is correct ?
285345.png
  • $$ \overrightarrow a + \overrightarrow b = 2 \overrightarrow c $$
  • $$ \overrightarrow a + \overrightarrow b = \overrightarrow c $$
  • $$ \overrightarrow a - \overrightarrow b = 2 \overrightarrow c $$
  • $$ \overrightarrow a - \overrightarrow b = \overrightarrow c $$
A car runs at constant speed on a circular track of radius $$10\ m$$ taking $$6.28\ s$$ on each lap. The average speed and average velocity on each complete lap is
  • Velocity $$10\ m/s$$, speed $$10\ m/s$$
  • Velocity $$0$$, speed $$10\ m/s$$
  • Velocity $$0$$, speed $$0$$
  • Velocity $$10\ m/s$$, speed $$0$$
The equation of the path of the projectile is $$y=0.5x-0.04x^{2}$$ The initials speed of the projectile is 
  • $$10\;m/s$$
  • $$15\;m/s$$
  • $$12.5\;m/s$$
  • None
Following sets of three forces act on a body. Whose resultant cannot be zero ?
  • 10, 10, 10
  • 10, 10, 20
  • 10, 20, 20
  • 10, 20, 40
A body moves along a curved path of a quarter circle.Calculate the ratio of distance to displacement :
  • $$11:7$$
  • $$7:11$$
  • $$11:7\sqrt{2}$$
  • $$7:11\sqrt{2}$$
Statement-1: Electric curent is a scalar quantity 
and
Statement -2: Electric current does not obey law of vector addition 
  • Statement -1 is True Statement -2 is True;

    Statement -2 is a correct explanation for Statement -1
  • Statement -1 is True Statement -2 is True;

    Statement -2 is NOT a correct explanation for Statement -1
  • Statement -1 is True Statement -2 is False;
  • Statement -1 is False Statement -2 is True;
Velocity - Time graph of a particle is given. Which of the following statement(s) is/are correct.
318921.png
  • net displacement is zero
  • total distance travelled is 80 metre
  • acceleration of the particle is constant
  • direction of velocity is constant
A body is projected horizontally from the top of a tower with initial velocity $$18\ ms^{-1}$$. It hits the ground at angle $$45^{\circ}$$. What is the vertical component of velocity when strikes the ground?
  • $$18 \sqrt{2}\, ms^{-1}$$
  • $$18 ms^{-1}$$
  • $$9 \sqrt{2}\, ms^{-1}$$
  • $$9 ms^{-1}$$
For four particles A, B, C & D, the velocities of one with respect to other are given as $$\bar{V}_{DC}$$ is 20 m/s towards north,  $$\bar{V}_{BC}$$ is 20 m/s towards east and $$\bar{V}_{BA}$$ is 20 m/s towards south. Then $$\bar{V}_{DA}$$ is:
  • 20 m/s towards north
  • 20 m/s towards south
  • 20 m/s towards east
  • 20 m/s towards west.
The maximum and minimum magnitudes of the resultant of two forces are 17 newton and 7 newton respectively, if these two forces are acting at right angle to each other, then the value of resultant of these forces in newton will be:
  • 10
  • 12
  • 13
  • 24
A particle is dropped from height 100 m and another particle is projected vertically up with velocity 50 m/s from the ground along the same line. Find out the height where two particle will meet? (take g = 10 $$m/s^2$$)
  • 100 m
  • 80 m
  • 120 m
  • 40 m
A fan is running at $$3000\ rpm$$. It is switched off. It comes to rest by uniformly decreasing its angular speed in $$10\ seconds$$. The total number of revolutions in this period.
  • $$150$$
  • $$250$$
  • $$350$$
  • $$300$$
0:0:1


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