Answer:
799.54 ft
Explanation:
Linear thermal expansion is:
ΔL = α L₀ ΔT
where ΔL is the change in length,
α is the linear thermal expansion coefficient,
L₀ is the original length,
and ΔT is the change in temperature.
Given:
α = 1.2×10⁻⁵ / °C
L₀ = 800 ft
ΔT = -17°C − 31°C = -48°C
Find: ΔL
ΔL = (1.2×10⁻⁵ / °C) (800 ft) (-48°C)
ΔL = -0.4608
Rounded to two significant figures, the change in length is -0.46 ft.
Therefore, the final length is approximately 800 ft − 0.46 ft = 799.54 ft.
Answer:
0.25 m
Explanation:
Electromagnetic waves consist of oscillations of the electric and the magnetic field, oscillating in a plane perpendicular to the direction of motion the wave.
All electromagnetic waves travel in a vacuum always at the same speed, the speed of light, whose value is:
Microwave is an example of electromagnetic waves.
The relationship between wavelength and frequency for an electromagnetic wave is:
![\lambda=\frac{c}{f}](https://tex.z-dn.net/?f=%5Clambda%3D%5Cfrac%7Bc%7D%7Bf%7D)
where
is the wavelength
is the speed of light
f is the frequency
For the microwave in this problem,
![f=1.2\cdot 10^9 Hz](https://tex.z-dn.net/?f=f%3D1.2%5Ccdot%2010%5E9%20Hz)
So its wavelength is
![\lambda=\frac{3.0\cdot 10^8}{1.2\cdot 10^9}=0.25 m](https://tex.z-dn.net/?f=%5Clambda%3D%5Cfrac%7B3.0%5Ccdot%2010%5E8%7D%7B1.2%5Ccdot%2010%5E9%7D%3D0.25%20m)
Yes. Acceleration means any change in speed or direction of motion. When an object coasts in a circular orbit at constant speed around the Earth, its direction is constantly changing. The acceleration is "CENTRIPETAL", which points toward the center of the circle.