1.
A violin is a musical instrument, which produces notes of specific pitch (frequency) using the vibration of a metal string. The violinist controls the pitch by pressing a finger down on the string, which effectively changes the length of the vibrating string.
The “A” string on a violin is roughly 330 mm long, and, when released completely, produces a
frequency of 440 Hz. Given that the note D is 587.3 Hz, what is the distance between the bridge and
the finger at the note D?Deselect Answer
2.
The maglev train is a special type of high-speed train, which uses electromagnets to levitate the train over the tracks. Thanks to the complete lack of friction, maglev trains are able to achieve very high speeds.
Let us study how the train levitates. There are permanent magnets on the bottom of the train, and
electromagnets on the tracks. By providing power to the electromagnets, they generate a magnetic
field, thus repelling the permanent magnets and applying an upwards force on the train. Because
the magnetic field is stronger at shorter distances, for the same amount of power, the repulsion
is stronger when the train is lower, and weaker when the train is higher.
Imagine a train that is levitating; the power of the electromagnets is perfectly tuned, so that the train
is hovering stationarily at a specific height. Suddenly, the power is decreased by a very small
amount.
What happens?Deselect Answer
3.
A ball with mass m is thrown into a basket, at a distance L away.
What is the minimum amount of kinetic energy needed to achieve this?Deselect Answer
4.
4. Diffusion at higher temperatures is faster. This means that the speed of movement of molecules and temperature are related. When the temperature rises, the speed of movement of the molecules increases; when the temperature is low, it decreases.
Consequently, the body temperature depends on the speed of movement of the molecules.
Fig 1.0 is the graph of temperature against time.
What of the following is correct?Deselect Answer
