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Class 11 Physics MCQ Questions of Motion in a Plane with Answers?

Answer 1

MCQ Questions for Class 11 Physics Motion in a Plane with Answers are set up according to the Latest Exam Pattern. These MCQ Questions for Class 11 Physics with answers clear for a fast revision. Students are encouraged to practice the Class 11 Physics MCQ Questions of Motion in a Plane with Answer is accessible here. 

Motion in a Plane is a very important concept in Physics, which basically describes the change in position of an object over a period of your time. Motion in a Plane will be represented with the assistance of the following terms such as:

• Displacement
• Distance
• Velocity
• Acceleration
• Time
• Speed

You can start practice with MCQ Question for class 11 with Answers for Board Exams.

Practice MCQ Questions for class 11 Physics Chapter-Wise

1. The angular velocity depends upon the rate of change of the?

(a) Angular acceleration
(b) Angular Distance
(c) Angular Displacement
(d) torque

2. A small body attached at the end of an inextensible string completes a vertical circle, then its

(a) angular momentum remains constant
(b) linear momentum remains constant
(c) angular velocity remains constant
(d) total mechanical energy remains constant

3. A body is travelling in a circle at a constant speed. It

(a) has a constant velocity
(b) is not accelerated
(c) has an inward radial acceleration
(d) has an outward radial acceleration

4. When a body P moves on a circular path, the centripetal acceleration is

(a) directed inwards from P, to the centre of the circle
(b) directed tangential to the circumference of the circle, at P
(c) directed perpendicular to the planc of the circle, at P
(d) directed outward, perpendicular to the circumference of the circle

5.  The path followed by a projectile is called its?

(a) Territory
(b) Treasury
(c) Tractor
(d) Trajectory

6. One radian is defined to be the angle subtended where the arc length S is exactly equal to the?

(a) radius of the circle
(b) diameter of the circle
(c) circumference of the circle
(d) half of radius of the circle

7. A car sometimes overturns while taking a turn. When it overturns, it is

(a) the inner wheel which leaves the ground first
(b) either inner wheel or the outer wheel leaves the ground
(c) both the wheel leave the ground simultaneously
(d) the outer wheel which leaves the ground first

8. The centripetal component of acceleration arises when? 

(a) The direction of motion is changed
(b) The direction propagation is changed
(c) The direction of gravity is changed
(d) The direction of projectile is changed

 Answer : (a) The direction of motion is changed

9. The word centripetal is derived from two Greek words meaning?

(a) Seeking the situation
(b) Seeking the centre
(c) Touching the centre
(d) Leaving the centre

10. A body is moving along a circle with an increasing speed. It possesses?

(a) centripetal acceleration only (ac)
(b) tangential acceleration only (ar)
(c) both tangential and centripetal acceleration (a_r and a_c)
(d) No acceleration

11. Which of the following conditions are sufficient and essential for a quantity to be a vector?

(a) Magnitude, direction, and addition, subtraction multiplication and division by vector laws
(b) Magnitude, direction and combination of vectors by ordinary rules of algebra
(c) Magnitude and addition, subtraction, multiplication by ordinary rules of algebra
(d) Magnitude and direction

12. How many minimum number of vectors in different planes can be added to give zero resultant?

(a) 4
(b) 5
(c) 3
(d) 2

13. Acceleration due to gravity

(a) polar vector
(b) a scalar
(c) a vector
(d) None of these

14. The resultant of A × 0 will be equal to

(a) zero vector
(b) zero
(c) A
(d) unit vector

15. For motion in two or three dimensions, the angle between velocity and acceleration is

(a) Any angle between 0° & 180°
(b) 180°
(c) 90° ​​​​​​
(d) 0°

16. Centripetal acceleration is

(a) not a constant vector
(b) a magnitude changing vector
(c) a constant scalar
(d) a constant vector

17. The direction of the angular velocity vector is along

(a) the axis of rotation
(b) the outward radius
(c) the inward radius
(d) the tangent to the circular path

18. Two bullets are fired horizontally and simultaneously towards each other from roof tops of two buildings 100 m apart and of same height of 200m with the same velocity of 25 m/s. When and where will the two bullets collides. (g =10 m/s²)

(a) after 2s at a height 180 m
(b) after 2s at a height of 20 m
(c) after 4s at a height of 120 m
(d) they will not collide

19. A projectile is fired from the surface of the earth with a velocity of 5 m/s and angle θ
with the horizontal. Another projectile fired from another planet with a velocity of 3 m/s at the same angle follows a trajectory, which is identical to the trajectory of the projectile fired from the earth. The value of the acceleration due to gravity on the planet (in m/s²) is: [Given, g = 9.8 m/s²]

(a) 3.5
(b) 5.9
(c) 16.3
(d) 110.8

20. In a uniform circular motion, which of the following quantity is not constant

(a) Angular momentum
(b) Speed
(c) Kinetic energy
(d) Momentum

21. A train is moving towards east and a car is along north, both with same speed. The observed direction of car to the passenger in the train is 

(a) East-north direction
(b) West-north direction
(c) South-east direction
(d) None of these

22. If the body is moving in a circle of radius r with a constant speed v, its angular velocity is:

(a) v²/r
(b) vr
(c) v/r
(d) r/v

23. A particle moves with constant angular velocity in a circle. During the motion its

(a) Energy is conserved
(b) Momentum is conserved
(c) Energy and momentum both are conserved
(d) None of the above is conserved

24.  A bomb is dropped from an aeroplane moving horizontally at constant speed. When air resistance is taken into consideration, the bomb 

(a) Falls to earth exactly below the aeroplane
(b) Fall to earth behind the aeroplane
(c) Falls to earth ahead of the aeroplane
(d) Flies with the aeroplane

25. A particle is moving in a horizontal circle with constant speed. It has constant

(a) Velocity
(b) Acceleration
(c) Kinetic energy
(d) Displacement

Answer 2

1. Answer : (c) Angular Displacement

Explanation: The orbital angular velocity vector encodes the time rate of change of angular position, as well as the instantaneous plane of angular displacement.

2. Answer : (d) total mechanical energy remains constant

Explanation: Mass of the system is constant and no word is done by any external force (no force is acting in direction of motion only force acting is tension force which is perpendicular to the velocity of the ball so work done is zero) so mechanical energy of the system is conserved.

3. Answer : (c) has an inward radial acceleration

Explanation: Body moves with constant speed it means that tangential acceleration a_T = 0 & only centripetal acceleration a_C exists whose direction is always towards the centre or inward

4. Answer : (a) directed inwards from P, to the centre of the circle

Explanation: So for an object moving in a circle, there must be an inward force acting upon it in order to cause its inward acceleration. This is sometimes called as centripetal force.

5. Answer : (d) Trajectory

Explanation: The path followed by a projectile is called its trajectory.

6. Answer : (a) radius of the circle

Explanation: One radian is defined as the angle subtended from the center of a circle which intercepts an arc equal in length to the radius of the circle.

7. Answer : (a) the inner wheel which leaves the ground first

Explanation: The inner wheel which leaves the ground first. Because the reaction on inner wheel decreases and becomes zero.

8. Answer : (a) The direction of motion is changed

Explanation: The acceleration of a body traversing a circular path. Because velocity is a vector quantity (that is, it has both a magnitude, the speed, and a direction), when a body travels on a circular path, its direction constantly changes and thus its velocity changes, producing an acceleration.

9. Answer : (b) Seeking the centre

Explanation: The word'centripetal'is derived from two Latin words 'centrum 'and 'petus' that translate into'center'and'seeking. 'Thus, centripetal acceleration is instantaneous acceleration that 'seeks the center' of the circle, or is directed toward the center of the circle.

10. Answer : (c) both tangential and centripetal acceleration (a_r and a_c)

Explanation: If a body is moving with increasing velocity on a circular path, it possesses both tangential and centripetal acceleration. If velocity is constant, it possesses centripetal acceleration.

11. Answer : (a) Magnitude, direction, and addition, subtraction multiplication and division by vector laws

Explanation: A vector quantity is defined as the quantity which has magnitude and direction and for which all the mathematical operations are possible only through vector laws.

12. Answer : (a) 4

Explanation: If the vectors are in different planes, they would need to cancel components in at least 3 dimensions to make the resultant 0. Hence, we would need at least 4 vectors such that 3 of them when added cancel their components in a plane and add to get a single vector perpendicular to this plane.

13. Answer : (a) polar vector

Explanation: Acceleration is the rate at which the velocity of a body changes with time. It has both magnitude and direction but its direction is not decided by its rotation about any axis like non polar vectors (axial), hence it is a polar vector.

14. Answer : (a) zero vector

Explanation: The cross product  vector A x B it a vector, with its direction perpendicular to both vector A and B. A x B is area. If side B is zero, area is zero. vector A x 0 is a zero vector.

If in case 0 is a scalar, then also the product is zero. But a scalar x a vector is also a vector. Hence one gets a zero vector in any case.

15. Answer : (a) Any angle between 0° & 180° 

Explanation: For motion of two or three dimension, the angle between velocity and acceleration vector should be between 0 and 180 degree. If the angle is 0 degree then the body will move in only one direction.

16. Answer : (a) not a constant vector

Explanation: A magnitude changing vector. Since velocity and radius are constants for a given uniform circular motion, so the magnitude of centripetal acceleration is also always constant. But, the direction of centripetal acceleration changes continuously in the circular path.

17. Answer : (a) the axis of rotation

Explanation: \(v=r\times\omega\)

v is the tangential. If r is in the XY plane and v is also in this plane,w is in the Z direction. + or − is decided by whether the particle is rotating in the anticlockwise direction or clockwise direction.

18. Answer : (a) after 2s at a height 180 m

Explanation: t = d/v_rel

= 100/50

= 2s

s_y = −1/2gt² 

= -1/2 x 10 x 4

= -20

∴ H = 180m

19. Answer : (a) 3.5

Explanation: For same trajectory both should have same horizontal range and maximum heights

⇒ 5²/g = 3²/a

⇒ a = 9.8 x 9/25

= 3.5

20. Answer : (d) Momentum

Explanation: The linear momentum doesn't remain constant as momentum is mass x velocity and the direction of velocity keeps on changing. Whereas mass, speed and kinetic energy remain constant over the uniform circular motion

21. Answer : (b) West-north direction

Explanation: For a passenger in the train, the car has one velocity component in the north direction due to its absolute motion and another velocity component in the west direction due to relative motion with respect to the passenger (since the train is moving along east).

tanθ = (-v/v)

θ = 135°

22. Answer : (c) v/r

Explanation: v = rω

∴ω =v/r = constant [As v and r are constant]

23. Answer : (a) Energy is conserved

Explanation: KE \(\propto\) v²

P = mv . In uniform circular motion (constant angular velocity) kinetic energy remains constant but due to change in velocity of particle its momentum varies.

24. Answer : (b) 

Explanation: If there is no resistance, bomb will drop at a place exactly below the flying aeroplane. But when we take into account air resistance, bomb will face decceleration in its velocity. So it will fall on the earth exactly behind aeroplane.

25. Answer : (c) 

Explanation: If an object is moving in a horizontal circle at constant speed, the centripetal force does not do work and cannot alter the total mechanical energy of the object. For this reason, the kinetic energy and therefore, the speed of the object will remain constant. 

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