Section 1 review
Circular motion can involve rotating, rolling, or orbiting objects. Any object moving in a circle is undergoing centripetal acceleration, which changes the direction of the velocity vector, but not its magnitude (speed). A centripetal force—directed toward the center of the circle—is required to maintain an object in circular motion. Read the text aloud
angular velocity, radian (rad), centripetal force, centripetal acceleration

ω= Δθ Δt
F c = m v t 2 r

Review problems and questions

  1. Radians and degrees are related by π rad = 180°. Perform the following conversions and draw each one of these angles on a circle.
    1. Convert 45° to radians
    2. Convert 0.5236 radians to degrees
    3. Convert 270° to radians
    4. Convert 7.85 radians to degrees
    5. Convert 585° to radians Read the text aloud Show
  1. A wheel spins at a rate of 30 revolutions per minute (rpm). What is the angle that a point on the wheel makes in one second? Give your answer in degrees and radians. Read the text aloud Show
  1. A race car is moving with a speed of 200 km/hr on a circular section of a race track that has a radius of 300 m. The race car and the driver have a combined mass of 800 kg.
    1. What is the magnitude of the centripetal acceleration felt by the driver?
    2. What is the centripetal force acting on the car? Read the text aloud Show
  1. A bicycle moves with a speed of 30 km/hr. If the wheels of the bicycle have a radius of 35 cm, what is the angular speed of the wheels?
    Give your answer in rad/s and degrees/s. Read the text aloud Show
  1. A 62 kg student rides a Ferris wheel that has a diameter of 50 m and makes one complete rotation every 35 s.
    1. What is the angular velocity of the wheel (in radians per second)?
    2. What is the linear velocity of the student (in meters per second)?
    3. What is the centripetal force acting on the student? Read the text aloud Show

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