The wrong type of lens-Microscope, concave
Explanation:
A microscope Basically uses t<u>wo convex lenses to magnify an object, or specimen.</u>
There are 2 lenses in a microscope
- <u>Object Lens:</u>The lens that is closer to the object
- <u>Eyepiece:</u>The lens that is closer to the eye
Both the object lens and the eyepiece, is a convex lens.
Answer:
434 Hz
Explanation:
According to the Doppler effect, when a source of a wave is moving towards an observer at rest, then the observer will observe an apparent frequency which is higher than the original frequency of the source.
In this situation, Tina is driving towards Rita. Tina is the source of the sound wave (the horn), while RIta is the observer. Since the original frequency of the sound is 400 Hz, Rita will hear a sound with a frequency higher than this value.
The only choice which is higher than 400 Hz is 434 Hz, so this is the frequency that Rita will hear.
<span>A bike is compound machine.This means that it is made up of a bunch of different simple machines. Screws are used to hold the pieces together. The wheel of a bicycle is a wheel and axle. The pedals are also examples of this simple machine. The pedals are attached to a lever that turns a pulley.</span>
Answer:
M = 175 kg
Explanation:
In the resolution of the harmonic oscillator movement of a system and a mass with a spring, the angular velocity is
w = √ k / m
Where k is the spring constant and m the mass
In this case the mass is the mass of the chair (m) plus the mass of the astronaut (M)
M all = m + M
The angular velocity and the period are related by
w = 2π / T
Substituting
2π / T = √(k/(m + M))
We calculate the astronaut's mass
4π² / T² = k / (m + M)
M = k T² / 4π² - m
M = 569 3.6² /(4π²) - 11
M = 186.8 - 11
M = 175 kg
