About Uniform Circular Motion

If you're looking to improve your understanding of physics, one important concept to learn is uniform circular motion. In this post, we will discuss what uniform circular motion is and how to use it in real-world situations. We'll also provide some examples so you can see this type of motion in action. Understanding uniform circular motion is an essential part of mastering physics, so don't miss out on this valuable information!

Uniform circular motion is defined as a type of motion where an object moves in a circle at a constant speed. The key word here is "constant." This means that uniform circular motion only occurs when an object's speed does not change as it moves around the circle. If an object's speed were to increase or decrease, then it would no longer be uniform circular motion.

One example of uniform circular motion is a car driving around a roundabout. The car's speed may vary as it enters and exits the roundabout, but while it is actually going around the circle, its speed should remain constant. Another example is a satellite orbiting the earth. The satellite's speed also remains constant as it circles the earth.

So how do we use uniform circular motion in the real world? One common application is in roller coasters. When a roller coaster goes around a loop, it is experiencing uniform circular motion. The key to making sure the roller coaster doesn't fly off the track is to make sure that its speed is constant.

Following are some of the multiple choice questions on the Uniform Circular Motion with answers that will help the students in developing their knowledge.

Uniform Circular Motion MCQ

1. How many radians does a circle have?

  • 360 degrees
  • 2π radians
  • π radians
  • 2 radians

2. A specific vehicle can go around a curve with a radius of 150 m with a maximum speed of 32 m/s without sliding off the road. To have the same acceleration, at what maximum speed can the same vehicle go around a curve having a radius of 75 m?

  • 45 m/s
  • 32 m/s
  • 23 m/s
  • 16 m/s

3. What can be said of an object in uniform circular motion?

  • It has a constant velocity.
  • It is an example of Newton's First Law in the absence of a force.
  • It has a constant tangential speed.
  • none of the choices given

4. Which one of the following statements concerning the two “gravitational constants” G, the universal constant, and g the magnitude of the acceleration due to the gravity is true?

  • The value for G and g do not depend on location. 
  • The value of G is the same everywhere in the universe, but the value of g is not. 
  • The value of G and g are equal on the surface of any planet, but in general, vary with location in the universe. 

5. When an object experiences uniform circular motion, the direction of the acceleration is A) in the same direction as the velocity vector. B) in the opposite direction of the velocity vector. C) is directed toward the center of the circular path. D) is directed away from the center of the circular path.

  • A
  • B
  • C
  • D

6. A grindstone spinning at the rate of 8.3 rev/s has what approximate angular speed?

  • 3.2 rad/s
  • 26 rad/s
  • 52 rad/s
  • 81 rad/s

7. Acceleration causes a change in velocity so acceleration can cause

  • a change in speed only.
  • a change in speed or direction.
  • a change in direction only.
  • All of above

8. A particle moves in a circular path of radius r with speed v. It then increases it speed to 2v while traveling along the same circular path. By what factor has the centripetal acceleration of the particle changed?

  • 0.25
  • 0.5
  • 2
  • 4

9. If the radius of a body moving in a circle with a uniform speed is doubled, its centripetal acceleration becomes:

  • Twice
  • Three times
  • Four times
  • half

10. Which of the following is a unit of acceleration?

  • m/s
  • m/s2
  • m.s2
  • m/s.s

11. What is the most direct cause of a car's centripetal acceleration as it rounds a curve?

  • The force of the steering wheel
  • The weight of the car.
  • The normal force exerted by the road.
  • The friction between the tires and the road.

12. What force keeps an object moving in a circle?

  • centripetal force (inward)
  • centrifugal force (outward)

13. What type of acceleration does an object moving with constant speed in a circular path experience? A) free fall B) constant acceleration C) linear acceleration D) centripetal acceleration

  • A
  • B
  • C
  • D

14. Which statement is true about an object that is traveling in uniform circular motion?

  • The speed of the object varies.
  • The net force on the object is directed toward the center of the circular path.
  • The direction of the object's velocity is constant.
  • The net force on the object is directed away from the center of the circular path.

15. A ceiling fan with 16 inch blades rotates at 45 rpm. Find the angular velocity of the fan in rad/min. Round to the nearest tenth.

  • 90 rad/min
  • 282.7 rad/min
  • 45 rad/min
  • 141.4

16. Which is true about centripetal force and centripetal acceleration?

  • The centripetal acceleration is always pointing toward the center of an orbit and the centripetal force is always pointing outward
  • The centripetal acceleration is always pointing outward from the center of an orbit and the centripetal force is always pointing inward
  • The centripetal acceleration is always pointing toward the center of an orbit and the centripetal force also pointing toward the center but in a totally different location
  • The centripetal acceleration is always pointing toward the center of an orbit and the centripetal force also pointing toward the center and in the same exact location as the centripetal acceleration

17. If an object is spinning around on a string and the string was suddenly cut, the object would move in a

  • curved path
  • straight line

18. What's the centripetal force of a 0.2 kg yoyo spun in a circle with a radius of .7 meters at a velocity of 3 m/s?

  • 2.05 N
  • 2.57 N
  • 2.90 N
  • 3.13 N

19. When an object is moving in a circle, its linear velocity is often called its __________ velocity.

  • centripetal
  • tangential
  • gravitational
  • centrifugal

20. What happens to the centripetal force exerted on an object if you triple the velocity?

  • it increases to 3X
  • it decreases to 6X
  • it increases to 6X
  • it increases to 9X

21. A horse gallops around a circular arena. The centripetal force on the horse is ___.

  • directed outward
  • tension
  • directed toward the center of the arena
  • 9.8 N

22. What happens if you let go of the string when you spin the stopper around your head?

  • the stopper continues moving in a circle
  • the stopper moves in a straight line

23. An object is moving round a horizontal circle of radius 0.80 m, at a constant angular frequency of 20 rpm. The centripetal acceleration of the object is ___________.

  • 3.53 rad s-1
  • 3.73 rad/s

24. A 0.50-kg mass is attached to the end of a 1.0-m string. The system is whirled in a horizontal circular path. If the maximum tension that the string can withstand is 350 N. What is the maximum speed of the mass if the string is not to break? A) 700 m/s B) 26 m/s C) 19 m/s D) 13 m/s

  • A
  • B
  • C
  • D

25. If a stone is tied to the end of a string and whirled in a circle, the tension in a string provides:

  • Centripetal force
  • Centrifugal force
  • Pressure
  • Reaction

26. A rubber stopper on the end of string is swung steadily in a horizontal circle. In one trial, it moves at speed v in a circle of radius r. In a second trial, it moves at a higher speed 3v in a circle of radius 3r. In the second trial the acceleration is

  • the same as in the first trial
  • three times larger
  • one-third as large
  • nine times larger

27. Two masses m and M are separated by a distance d. If the distance between the masses is increased to 3d, how does the gravitational force between them change?

  • becomes 1/3 as great
  • 1/9 as great
  • 3x greater
  • 9x greater

28. Convert π/4 radians to degrees

  • 90⁰
  • 45⁰
  • 60⁰
  • 30⁰

29. Determine the angular velocity in rad/min of a gyroscope rotating at 6 rps (revolutions per second). Leave answer in terms of π.

  • 360π rad/min
  • 12π rad/min
  • 360 rad/min
  • 720π rad/min

30. Is it possible for an object moving with a constant speed to accelerate? Explain. A) No, if the speed is constant then the acceleration is equal to zero. B) No, an object can accelerate only if there is a net force acting on it. C) Yes, although the speed is constant, the direction of the velocity can be changing. D) Yes, if an object is moving it can experience acceleration

  • A
  • B
  • C
  • D

31. An object moves in a circular path at a constant speed. Compare the direction of the object's velocity and acceleration vectors. A) Both vectors point in the same direction. B) The vectors point in opposite directions. C) The vectors are perpendicular. D) The question is meaningless, since the acceleration is zero

  • A
  • B
  • C
  • D

32. An object moves in a circle. The net force is 5.0 N. If the student doubles the speed, what force is needed? ΣFnet = mv2r\Sigma F_{net}\ =\ \frac{mv^2}{r}ΣFnet​ = rmv2​

  • 2.5 N
  • 5.0 N
  • 10.0 N
  • 20.0 N

33. The velocity is always _____ to the line of a circle.

  • outwards
  • towards the center
  • tangent
  • faster

34. A 3.0 N centripetal force acts on a toy car, if the car's mass is doubled then the force is... ΣFnet = mv2r\Sigma F_{net}\ =\ \frac{mv^2}{r}ΣFnet​ = rmv2​

  • 3.0 N
  • 6.0 N
  • 9.0 N
  • 1.5 N

35. An object moves with a constant speed of 30 m/s on a circular track of radius 150 m. What is the magnitude of the acceleration of the object? A) zero B) 0.17 m/s2 C) 5.0 m/s2 D) 6.0 m/s2

  • A
  • B
  • C
  • D

36. If a ball is swinging at the end of a rope and the rope is suddenly cut, assuming there is no gravity, what best describes the path it will take?

  • It will fly in a straight line forward from where it was cut
  • It will fly in a curved line away from the circle
  • It will fly inward toward the circle
  • None of these

37. An object in uniform circular motion is (choose all that apply)

  • traveling at a constant speed
  • accelerating
  • not accelerating
  • Both A & B

38. For an object to be in uniform circular motion the direction of the acceleration is

  • perpendicular to the direction of travel.
  • parallel to the direction of travel.
  • diagonally inwards between the direction of travel and the center of the circle.
  • diagonally outwards away from the center of the circle but in the same direction of travel.

39. A spin balancer rotates the wheel of a car at 500 revolutions per minute. What is the angular speed in degrees per second?

  • 16.67 deg / sec
  • 6,000 deg / 1 sec
  • 3,000 deg / 1 sec
  • 180,000 deg / 1 sec

40. Calculate the amount of centripetal force it takes for a softball pitcher to rotate a ball with a velocity of 3 m/s if the ball weigh 0 .12 kg and her arm is 0.65 meters long.

  • 0.38
  • 1.23
  • 0.55
  • 1.66 N

41. Determine the linear velocity of the tips of the blades for a ceiling fan with 2.000 m blades rotating at 45.00 rpm. (give in SI Units)

  • 565.5 m/s
  • 180 m/s
  • 282.7 m/s
  • 90 m/s

42. The wheels of a car have radius 0.330 m. and are rotating at 600.0 rpm. Determine the speed of the car in miles/hour to the nearest tenth. (Determine ω (angular velocity) first and then use v=ω⋅r and convert to km/hour)

  • 11.88 km/hour
  • 685.4 km/hour
  • 74.64 km/hour
  • 74640 km/hour

43. Calculate the mass of an object if it took 20 N to rotate it in a circle with a radius of 2 meters with a velocity of 4 m/s

  • 4.1 kg
  • 3.6 kg
  • 2.5 kg
  • 1.8 kg

44. Two bugs ride a turntable which is rotating at a constant rate of 4 rad/s. Bug A is at a radius of 4 cm, while bug B is at a radius of 8 cm. Which of the following is true?

  • Bug A has a greater angular velocity
  • Bug B has a greater angular velocity.
  • Bug A has a greater linear velocity.
  • Bug B has a greater linear velocity.

45. Determine the central angle if the arc length is 10 cm and the radius is 5 cm. Convert to degrees.

  • not possible ... "s" is too small
  • ≈ 114.6°
  • 360°

46. Centripetal acceleration acts towards the ___________ of the circular motion

  • centre
  • circumference

47. Centripetal force is...

  • the resultant force acting on a body moving at constant speed in a circle 
  • the outwards force acting on a body moving at constant speed in a circle 

48. Calculate the velocity of an object moved around a circle with a radius of 1.65 m and an acceleration of 3.5 m/s2.

  • 2.4 m/s
  • 3.6 m/s
  • 3.9 m/s
  • 4.2 m/s

49. A particle moves in a horizontal circle of radius 0.60 m with a constant speed and a period of revolution of 0.02 s. The linear velocity of the particle is ____________.

  • 188.50 m/s
  • 188.70 ms-1

50. A 1.3 m long fishing line rated as "10 lb test" that can stand a force of 10 lb (44.48 N) is attached to a rock of mass 0.5 kg. The maximum speed at which the rock can be rotated without breaking the line is __________.

  • 10.75 ms-1
  • 10.95 m/s

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