Periodic motion and waves
Why do objects rotate and oscillate, and how do waves travel?
17 lessons
Lessons
Rotation and equilibrium
Chapter 1Moment: the turning effect of a forceWhy does a stuck wheel nut come loose with a long spanner, when the same force on a short spanner cannot make it budge?
- Chapter 2Equilibrium of a body: forces and moments
Why can a paint can be placed on the overhang of a plank lying across trestles, but only up to a certain point before the plank topples?
Circular motion and gravitation
Chapter 3Moving in a circle: period and speedWhy does a child standing at the edge of a roundabout rush along much faster than a child standing next to the centre pole, even though both complete a turn equally fast?
- Chapter 4Centripetal acceleration and the equation of motion in a circle
Why does a car slide off the road on a slippery bend?
- Chapter 5The gravitational force between bodies
Why does a dropped apple rush towards the Earth, while the Earth does not seem to move towards the apple at all?
- Chapter 6Satellites and planets in circular orbits
Why does the International Space Station ISS not fall to the Earth, and why do the astronauts float inside it?
Oscillations
Chapter 7Describing oscillation: period, frequency and amplitudeWhy can the motion of a child on a swing be described with a few numbers, even though the swing is in a different place at every moment?
- Chapter 8Spring force and spring energy
Why does a pinball launcher shoot the ball faster the further its spring is compressed?
- Chapter 9The mass–spring oscillator and the pendulum
Why does every swing, pendulum and body bobbing on a spring oscillate at its own pace, and what determines that pace?
Waves
Chapter 10How waves form and travelWhy does a bell hanging on a post ring when the other end of a long rope is flicked once, although nobody touches the bell?
- Chapter 11A wave meets an obstacle or a gap
Why do waves reach the corners of a harbour through the narrow gap in a breakwater, and do not travel only straight to the place opposite the gap?
- Chapter 12When waves combine: superposition and interference
Why does the sound sometimes get louder and sometimes almost vanish when you walk in front of two loudspeakers playing the same tone?
- Chapter 13Standing waves: nodes, antinodes and natural frequencies
Why does a guitar string always sound the same note when it is plucked, and why does the note rise when the string is pressed against the fingerboard or tightened?
Sound
Chapter 14Sound as a wave: pitch, timbre and the Doppler effectWhy does the siren of a passing ambulance sound as if it drops in pitch just as it goes by, even though the siren itself keeps sounding exactly the same?
- Chapter 15Intensity and the decibel scale
Why is the loudness of a sound given in decibels and not in watts per square metre, and what does a decibel reading actually tell us?
- Chapter 16Noise, acoustics and sound reproduction
Why can a concert of a few hours damage hearing permanently, even though the sound does not feel painful?
- Chapter 17Applied chapter: ultrasound imaging and earthquake waves
Why can an ultrasound machine draw a picture of the inside of the body using nothing but echoes, and why is gel spread under the probe first?
Apply independently
At the end of the module you can try whether you can apply what you have learned independently, in the style of the matriculation examination. The model answers and marking guides open after your own solution.
- Apply independently 4 tasks · 64 points
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Module goals
Show all 4 goals
The student
- can model planetary motion as circular motion
- becomes familiar with the basics of oscillation and wave motion by investigating mechanical oscillation and sound
- can describe periodic motion with physical and mathematical concepts
- can model mechanical oscillation and sound as periodic motion