CBSE Class 11 Physics Motion in a Plane MCQs Set B

Question: The shape of trajectory of the motion of an object is determined by 
a) acceleration
b) initial position
c) initial velocity
d) All of these
Answer: d

Question: The velocity of projection of a body is increased by 2%.Other factors remaining unchanged, what will be the percentage change in the maximum height attained?
a) 1%
b) 2 %
c) 4 %
d) 8 %
Answer: c

Question: The resultant of A × 0 will be equal to 
a) zero
b) A
c) zero vector
d) unit vector
Answer: c

Question: A cricket ball is hit with a velocity 25 ms^–1, 60° above the horizontal. How far above the ground, ball passes over a fielder 50 m from the bat (consider the ball is struck very close to the ground)? Take 3 =1.7 and g = 10 ms^–2   
a) 6.8 m
b) 7 m
c) 5 m
d) 10 m
Answer: c

 Question: A particle moving with velocity vr == k( yiˆ + xˆj), where k = constant. The general equation for its path is  [C = constant]
a) y = x² + C
b) y² = x + C
c) xy = C
d) y² = x² + C
Answer: d

 Question: A particle moves in the X-Y plane with a constant acceleration 1.5 m/s² in the direction making an angle of 37° with the X-axis. At t = 0 the particle is at the origin and its velocity is 8.0 m/s along the X-axis. Find the position of the particle at t = 4.0 s.     
a) (41.6m, 7.2 m)
b) (50.3 m, 8.2 m)
c) (60.2 m, 8.2 m)
d) (11.2 m, 8 m)
Answer: a 

Question: Acceleration due to gravity     
a) a scalar
b) a vector
c) polar vector
d) None of these
Answer: c 

Question: A particle moves in a plane with a constant acceleration in a direction different from the initial velocity. The path of the particle is a/an   
a) straight line
b) arc of a circle
c) parabola
d) ellipse
Answer: c

Question: A missile is fired for maximum range with an initial velocity of 20 m/s. If g = 10 m/s², the range of the missile is   
a) 40 m
b) 50 m
c) 60 m
d) 20 m
Answer: a

Question: A body is thrown with a velocity of 9.8 ms^–1 making an angle of 30º with the horizontal. It will hit the ground after a time   
a) 3.0 s
b) 2.0 s
c) 1.5 s
d) 1 s
Answer: d 

Question: Which of the following conditions are sufficient and essential for a quantity to be a vector?   
a) Magnitude and direction
b) Magnitude and addition, subtraction, multiplication by ordinary rules of algebra
c) Magnitude, direction, and addition, subtraction multiplication and division by vector laws
d) Magnitude, direction and combination of vectors by ordinary rules of algebra
Answer: c

Question: How many minimum number of vectors in different planes can be added to give zero resultant?   
a) 2
b) 3
c) 4
d) 5
Answer: c 

Question: A boat crosses a river with a velocity of 8 km/h. If the resulting velocity of boat is 10 km/h then the velocity of river water is       
a) 4 km/h
b) 6 km/h
c) 8 km/h
d) 10 km/h 
Answer: b 

Question: A person aiming to reach the exactly opposite point on the bank of a stream is swimming with a speed of 0.5 m/s at an angle of 120° with the direction of flow of water. The speed of water in the stream is       
a) 1 m/s
b) 0.5 m/s
c) 0.25 m/s
d) 0.433 m/s
Answer: c

Question: Two balls are projected at an angle q and (90º – q) to the horizontal with the same speed. The ratio of their maximum vertical heights is       
a) 1 : 1
b) tan q : 1
c) 1 : tan q
d) tan2 q : 1
Answer: d

Question: Two bullets are fired horizontally with different velocities from the same height. Which will reach the ground first?   
a) Slower one
b) Faster one
c) Both will reach simultaneously
d) It cannot be predicted
Answer: c

Question: If q is the angle between two vectors, then the resultant vector is maximum, when value of q is   
a) 0°
b) 90°
c) 180°
d) Same in all cases
Answer: a

 Question: A body projected at an angle with the horizontal has a range 300 m. If the time of flight is 6 s, then the horizontal component of velocity is       
a) 30 m s^–1
b) 50 m s^–1
c) 40 m s^–1
d) 45 m s^–1
Answer: b

Question: The greatest range of a particle, projected with a given velocity on an inclined plane, is x times the greatest vertical  altitude above the inclined plane. Find the value of x.     
a) 2
b) 4
c) 3
d) 1/2
Answer: b

Question: The coordinates of a particle moving in x–y plane at any instant of time t are x = 4t²; y = 3t². The speed of the particle at that instant is   
a) 10 t
b) 5 t
c) 3 t
d) 2 t
Answer: a 

Question: If the angles of projection of a projectile with same initial velocity exceed or fall short of 45° by equal amounts , then the ratio of horizontal ranges is    
a) l : 2
b) l : 3
c) 1 : 4
d) 1 : 1
Answer: d

 Question: At the highest point on the trajectory of a projectile, its   
a) acceleration is minimum 
b) velocity is maximum
c) acceleration is maximum
d) velocity is minimum
Answer: d

 Question: A particle has an initial velocity 3iˆ + 4 ˆj and an acceleration of 0.4iˆ + 0.3 ˆj . Its speed after 10 sec is  
a) 7 2 units
b) 7 units
c) 8.5 units
d) 10 units
Answer: a

Question: A bullet is fired with a speed of 1500 m/s in order to hit a Ntarget 100 m away. If g = 10 m/s². The gun should be aimed         
a) 15 cm above the target
b) 10 cm above the target
c) 2.2 cm above the target
d) directly towards the target
Answer: c

Question: A projectile is thrown in the upward direction making an angle of 60° with the horizontal direction with a velocity of 147 ms^–1. Then the time after which its inclination with the horizontal is 45°, is     
a) 15 s
b) 10.98 s
c) 5.49 s
d) 2.745 s
Answer: c 

Question: At the top of the trajectory of a projectile, the acceleration is
a) maximum
b) minimum
c) zero
d) constant (g)
Answer: d

 Question: The angle between the direction of ˆi and (iˆ + ˆj) is   
a) 90°
b) 0°
c) 45°
d) 180°
Answer: c

Question: The time of flight of a projectile on an upward inclined plane depends upon 
a) angle of inclination of the plane
b) angle of projection
c) the value of acceleration due to gravity
d) all of the options.
Answer: d

Question: A body is projected horizontally with velocity 3 m/s from a height 5m. It’s horizontal range is   
a) 3 m
b) 5 m
c) 10 m
d) 12 m
Answer: a

Question: Two stones are moving with same angular speeds in the radii of circular paths 1 m and 2 m. The ratio of their linear speed is ...X.... Here, X refers to     
a) 2
b) 1/2
c) 1/3
d) 3
Answer: b

Question: A boat which has a speed of 5 km/hr in still water crosses a river of width 1 km along the shortest possible path in 15 minutes. The velocity of the river water in km/hr is         
a) 3
b) 4
c) 21
d) 1
Answer: a 

Question: Centripetal acceleration is         
a) a constant vector
b) a constant scalar
c) a magnitude changing vector
d) not a constant vector
Answer: d 

Question: A stone is thrown from a point with a speed 5 m/s at an elevation angle of q. From the same point and at the same instant, a person starts running with a constant speed 2.5 m/s to catch the stone. If the person will be able to catch the ball then, what should be the angle of projection q?     
a) 75°
b) 30°
c) 60°
d) 45°
Answer: c

 Question: Two balls are projected simultaneously in the same vertical plane from the same point with velocities v1 and v₂ with angle q₁ and q₂ respectively with the horizontal. If v1 cos q1 = v₂ cos q₂, the path of one ball as seen from the position of other ball is :     
a) parabola
b) horizontal straight line
c) vertical straight line
d) straight line making 45° with the vertical
Answer: c 

Question: The range of a projectile is R when the angle of projection is 40°. For the same velocity of projection and range, the other possible angle of projection is   
a) 45°
b) 50°
c) 60°
d) 40°
Answer: b

Question: A body is projected from the ground with a velocity 50 m/s at an angle of 30°. It crosses a wall after 3 sec. How far beyond the wall the stone will strike the ground?    [take g = 10 m/s²]
a) 86.6 m
b) 96.2 m
c) 100.1 m
d) 111.1 m
Answer: a

Question: A river flow with a speed more than the maximum speed with which a person can swim in the still water. He intends to cross the river by shortest possible path (i.e., he wants to reach the point on the opposite bank which directly opposite to the starting point). Which of the following correct?  
a) He should start normal to the river bank.
b) He should start in such a way that, he moves normal to the bank, relative to the bank.
c) He should start in a particular (calculated) direction making an obtuse angle with the direction of water current.
d) The man cannot cross the river, in that way.
Answer: d 

Question: A stone is just released from the window of a moving train moving along a horizontal straight track. The stone will hit the ground following a       
a) straight line path
b) circular path
c) parabolic path
d) hyperbolic path
Answer: c

 Question: It is found that | A + B | = | A |. This necessarily implies,       
a) B = 0
b) A and B are antiparallel
c) A and B are perpendicular
d) A.B < 0
Answer: b

Question: A stone is projected horizontally with a 5 m/s from the top of a plane inclined at an angle 45o with the horizontal.   How far from the point of projection will the particle strike the plane?
a) 5 2m
b) 11 2m
c) 12 2m
d) 15 2m
Answer: a

Question: In the projectile motion, if air resistance is ignored, the horizontal motion is at   
a) constant acceleration
b) constant velocity
b) variable acceleration
d) constant retardation
Answer: c

 Question: For motion in two or three dimensions, the angle between velocity and acceleration is 
a) 0°
b) 90°
c) 180°
d) Any angle between 0° & 180°
Answer: d

Question: A plane flying horizontally at a height of 1500 m with a velocity of 200 ms^–1 passes directly overhead on antiaircraft gun. Then the angle with the horizontal at which the gun should be fired from the shell with a muzzle velocity of 400 ms–1 to hit the plane, is   
a) 90° 
b) 60°
c) 30°
d) 45°
Answer: b

Question: A moves with 65 km/h while B is coming back of A with 80 km/h. The relative velocity of B with respect to A is       
a) 80 km/h
b) 60 km/h
c) 15 km/h
d) 145 km/h
Answer: c

Question: A ball is thrown from rear end of the compartment of train to the front end which is moving at a constant horizontal velocity. An observer A sitting in the compartment and another observer B standing on the ground draw the trajectory. They will have   
a) equal horizontal and equal vertical ranges
b) equal vertical ranges but different horizontal ranges
c) different vertical ranges but equal horizontal ranges
d) different vertical and different horizontal ranges
Answer: b

Question: A projectile is fired from the surface of the earth with a velocity of 5 ms^–1 and angle q with the horizontal. Another projectile fired from another planet with a velocity of 3 ms^{– 1} at the same angle follows a trajectory which is identical with the trajectory of the projectile fired from the earth. The value of the acceleration due to gravity on the planet is (in ms^{– 2}) given g = 9.8 m/s²       
a) 3.5
b) 5.9
c) 16.3
d) 110.8
Answer: a

Question: Which of the following statements is/are incorrect?   
I. A scalar quantity is the one that is conserved in a process.
II. A scalar quantity is the one that can never take negative values.
III. A scalar quantity has the same value for observers
with different orientations of the axes.
a) I and III
b) II only
c) II and III
d) I and II
Answer: d

Question: Consider the following statements and select the correct statements from the following. 
I. Addition and subtraction of scalars make sense only for quantities with same units
II. Multiplication and division of scalars with different units is possible
III. Addition, subtraction, multiplication and division of scalars with same unit is possible
a) I and II
b) II and III
c) I and III
d) I, II and III
Answer: d

Question: Three vectors A, B and C add up to zero. Select the correct statements.   
I (A × B) . C is not zero unless B, C are parallel
II If A,B,C define a plane, (A × B) × C is in that plane
III (A × B) .C = | A | | B | C | → C2 = A2 + B2
a) I and II
b) II and III
c) I and III
d) I, II and III
Answer: c