Circular motion and angular velocityEdexcel A-Level Physics: Flashcards
What these 13 flashcards ask
- How many radians are there in a full circle?
- Define the radian.
- How do you calculate the angle in radians from an arc length?
- Define angular velocity.
- What is the relationship between ω and the period T?
- What is the relationship between ω and the frequency f?
- State the relationship between linear speed and angular velocity.
- How do you convert rpm to rad s⁻¹?
- Why is an object moving at constant speed in a circle accelerating?
- In which direction is the centripetal acceleration?
- State two expressions for centripetal acceleration.
- In the derivation of a = v²/r, what is the magnitude of the change in velocity for a small angle Δθ?
- What happens to the centripetal acceleration if the angular velocity doubles at constant radius?
Exam questions on Circular motion and angular velocity
- A fairground wheel of radius 12 m turns at a steady rate, completing one revolution every 40 s. A rider sits at the rim of the wheel.Calculate the magnitude of the rider's centripetal acceleration.2 marks
- A laboratory centrifuge rotor spins at a steady 6000 revolutions per minute. A sample tube holds its contents at a distance of 0.080 m from the axis of rotation.Calculate the speed of the contents of the tube.2 marks
- A small body moves at constant speed v in a horizontal circle of radius r. In a short time Δt it turns through a small angle Δθ, so that its velocity changes from v₁ to v₂, both of magnitude v. The Moon is such a body to a good approximation: it orbits the Earth in a circle of radius 3.84 × 10⁸ m with a period of 27.3 days.Show that the acceleration of the body is v²/r and state its direction.3 marks
Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).