WBCHSE Class 11 Physics Circular Motion Very Short Answer Questions

Circular Motion Very Short Answer Type Questions

Very Short Answer Questions on Circular Motion for Class 11

Question 1. Name the unit of angular displacement.
Answer:

The unit of angular displacement

Degree or radian

Question 2. State true or false—an angle measured in radians is dimensionless.
Answer: True

Question 3. What kind of vector is angular velocity?
Answer: Axial vector

Question 4. What is the angular velocity of the second hand of a clock?
Answer:

The angular velocity of the second hand of a clock

10.105 rad · s^-1

Question 5. Uniform circular motion is an example of uniform velocity’—state whether the statement is correct.
Answer: No

Question 6. What do you mean by the term frequency?
Answer:

Frequency

Complete rotation number per second

Question 7. What is the relation between time period and frequency?
Answer:

Relation between time period and frequency

v = \(\frac{1}{T}\)

Question 8. What is the dimension of angular acceleration?
Answer:

Dimension of angular acceleration

T^-2

Quetsion 9. 1 rps = ______ rpm = _______ rph
Answer: 60, 3600

Question 10. 1 rpm =? rad · s^-1
Answer: π/30

Question 11. What is the vector relation of linear acceleration \(\vec{a}\) and angular acceleration (\(\vec{alpha}\))?
Answer: \(\vec{a}\) = \(\vec{alpha}\) x \(\vec{r}\)

Question 12. In the case of uniform circular motion, the velocity and the acceleration are perpendicular to each other. [State true or false]
Answer: True

Question 13. What is the angular velocity of the minute hand of a clock in rad •· s^-1?
Answer: π/1800

Key Terms in Circular Motion: Very Short Answers

Question 14. If the frequency of revolution of a body is n, then what will be the velocity of revolution?
Answer: ω = 2πn

Question 15. A particle of mass m is moving in a circular path of radius r with a uniform speed v. The centripetal force on the body is \(\frac{m \omega^2}{r}\). When the particle is displaced half of the distance, then what is the work done by the centripetal force?
Answer: Zero

Question 16. What does supply the necessary centripetal force when a stone tied with a string is rotated along a circular Path?
Answer: Tension in the string

Question 17. What does provide a planet the necessary centripetal force to revolve around the sun?
Answer: The gravitational force of the sun

Question 18. If a particle moves in a circular path with constant speed, what should be the direction of its resultant acceleration?
Answer: Towards the centre

Question 19. In the case of railway tracks, which rail is to be kept at a slightly higher level near a bend?
Answer: Outer rail

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Question 20. The radius of a curved path is r and the coefficient of friction between a car and the path is μ. What is the maximum speed at which the car can turn at a bend without skidding?
Answer: \(V_m=\sqrt{\mu r g}\)

Question 21. Is it possible for a cyclist to lean through an angle of 45° with the vertical when he takes a turn?
Answer: No

Question 22. Why is a centripetal force so-called?
Answer: It is centre-seeking

Common Concepts in Circular Motion: Short Answers

Question 23. For uniform circular motion, does the direction of the centripetal force depend on the sense of rotation (i.e., clockwise or anti-clockwise)?
Answer: No

Question 24. A body is moving along a circular path such that its speed always remains constant. Should there be a force acting on the body?
Answer: Yes

Question 25. What type of acceleration does a body moving along a circular path possess?
Answer: Centripetal

Question 26. A piece of stone is tied with a thread and is rotated along a horizontal circular path. If the thread snaps suddenly, in which direction will the stone fly?
Answer: Tangentially

Question 27. What supplies the necessary centripetal force to the electrons in an atom to revolve around the nucleus?
Answer: Electrostatic force of attraction

Question 28. When a car turns towards the right while moving, the passengers inside the car lean towards _______.
Answer: Left

Question 29. To avoid an accident of a moving car near a bend, _______ force is supplied by banking the road.
Answer: Centripetal

Examples of Circular Motion with Very Short Answers

Question 30. A cyclist is riding on a cycle with speed v and while negotiating a circular path of radius r, he leans at an angle θ with the ground. Then, what will be the value of tanθ?
Answer: \(\frac{rg}{v^2}\)

Question 31. The angular momentum of a body of mass m rotating along a circular path of radius r with uniform speed is L. What is the magnitude of the centripetal force acting on it?
Answer: \(\frac{L^2}{mr^3}\)

Question 32. When a motor car moves speedily on a convex path, how do the passengers inside the car feel?
Answer: Lighter

Question 33. At which plane on earth, the centripetal force is maximum?
Answer: Equatorial plane

Question 34. Due to which type of force butter comes out during stirring of milk?
Answer: Centrifugal

Question 35. A body of mass m is rotated along a circular path of radius r with uniform speed v. Centripetal force acting on the body is \(\frac{m v^2}{r}\). If the body travels through a semicircular path, then what will be the work done by the centripetal force?
Answer: Zero